Britax One4Life Review – United States and Canada

(Last Updated On: December 24, 2022)
Britax One4Life 15 position adjustable headrest

Britax One4Life 15 position adjustable headrest

ClickTight technology was kind of a game-changer for car seat installations when it was introduced. Since we first met this technology on the now-retired Britax Frontier, we marveled at how simple it made installing a car seat! It’s found on the ClickTight convertible car seats — Marathon, Advocate, and Boulevard, the Grow With You forward facing only combination car seat, and now it’s an integral part of Britax’s newest offering — the One4Life multimode car seat.

This plush, long-lasting multimode car seat does many things (though not at the same time!): it rear faces, forward faces, then converts to a high back booster seat. In all modes, the installation or setup is pretty darn simple, which means that it’s easier to install and use correctly.

In addition to the ClickTight installation, the One4Life is packed with thoughtful details — sleek styling, a smooth shell, and bright, easy-to-read information labels. There’s even a helpful handle at the top of the seat to make removing the seat from the box (and carrying the seat to the vehicle) simple . All of this adds up to a pretty appealing option. Come along as we take a closer look.

CSFTL Quick Stats

  • Rear facing weight range: 5-50 pounds
  • Rear facing height range USA: until the child’s head is 1 inch below the top of the headrest
  • Rear facing height range Canada: less than 49 inches tall
  • Forward facing weight range: 22-65 pounds
  • Forward facing height range: less than 49 inches tall
  • High back booster weight range: 40-120 pounds
  • High back booster height range: 44-63 inches tall
  • CSFTL recommends that children be at least 5 years old before moving to a booster seat.
  • Lower anchor weight limit: 30 pounds rear facing, 35 pounds forward facing
  • Britax follows NHTSA’s guidelines for replacement after a crash
  • Allows up to 3 inches of overhang in harness mode
  • Does not allow any overhang in booster mode
  • In Canada, the anti-rebound bar must be used at all times when using the Britax One4Life rear facing (the Anti Rebound Bar is optional for users in the United States).


  • Crotch buckle positions: 4,6, and 7.5 inches from the back of the seat pan
  • Lowest harness position USA: 7 inches with insert, 8 inches without insert
  • Lowest harness position Canada: 5.5 inches with insert, 8 inches without insert
  • Highest harness position: 19 inches
  • Highest booster belt guide position: 21 inches
  • Width at widest point (at the cupholders): 19.5 inches
  • Seat pan: 14.5 inches tall
  • Seat weight: 30 pounds
  • Expiration: 10 years from the date of manufacture

Differences Between United States and Canada

We’re not talking about Tim Horton’s vs. Dunkn’ here, we’re just talking about the differences in this seat between the two countries. For the most part the seat’s limits and instructions are the same. Here are the key differences:

Rear facing height range

  • Rear facing height range Canada: less than 49 inches tall
  • Rear facing height range USA: until the child’s head is 1 inch below the top of the headrest

Lowest harness position with padding

  • Lowest harness position USA: 7 inches with insert, 8 inches without insert
  • Lowest harness position Canada: 5.5 inches with insert, 8 inches without insert

Anti-rebound bar

  • In Canada, the anti-rebound bar must be used at all times when using the Britax One4Life rear facing. The anti-rebound bar is optional for users in the United States.

One4Life for Both the United States and Canada

The rest of this review will address the features and usage guidelines for this seat in both countries.

ClickTight Installation System

Britax One4Life ClickTight installation label

Britax One4Life ClickTight installation label

When it comes to installation, the most notable part of the One4Life is Britax’s ClickTight installation system. This system includes an easy-to-open panel and some clearly marked belt paths — blue for rear facing and green for forward facing. Just open the panel, thread the vehicle seat belt through the exposed belt path, remove most of the slack from the belt, then close the panel. Don’t forget the top tether for forward facing installations!

In most cases, this rather simple set of instructions makes for a secure install! That ease of use is why we’re such fans of the ClickTight installation system.

Harness Webbing

Britax One4Life with diamond weave harness

The One4Life has a new type of harness webbing with a diamond-weave pattern. Britax let us know that this new pattern is stronger than traditional types of webbing. We found that this texture had a bonus feature — it was just a bit harder for a kiddo to move the chest clip around and the harness was less likely to twist.

Headrest Adjustment

Britax One4Life 15 position adjustable headrest

The headrest has 15 positions for a proper harness fit at every stage. It adjusts with a squeeze of the red button at the top of the headrest. Because it has all of those harness positions, Britax has modified the rules around headrest placement a bit — in rear facing mode, the harness must be at the nearest position below the child’s shoulders, in forward facing mode, the harness must be at the nearest position above the child’s shoulders.

Infant Insert*

The infant inserts are different styles and have different rules for users in Canada and in the United States:

United States:

One4Life insert USA

One4Life insert USA

The infant insert for models sold in the United States is one piece and is optional rear facing, but must be removed once the child weighs 20 pounds.


One4Life inserts Canada

One4Life inserts Canada

In Canada, the One4Life comes with an upper body support pillow and a lower infant insert.

The lower infant insert MUST be used until the child weighs 22 pounds and then it MUST be removed. This causes a bit of an issue with the crotch buckle length, and we’ll get into that more later in this review. The upper body support is optional but MUST be removed when the child weighs 20 pounds.

Both country’s inserts have their weight limits clearly marked on the insert.

Headrest Cover

One4Life folded cover

One4Life folded headrest cover

The headrest cover must also be unfolded when the seat is used for children who weigh more than 20 pounds.

One4Life unfolded headrest cover

One4Life unfolded headrest cover

That’s a little hard to explain, hopefully our photo says it best!

Cover Adjustment

The inside of the cover has some thoughtfully placed aplix squares that keep the cover in place when the headrest is folded. That aplix clearly indicates where the cover should sit.


Britax One4Life cupholder

Britax One4Life cupholder

The seat includes two cupholders — one for each side of the car seat. They’re removable for cleaning. We appreciated being able to take a cupholder right off the seat to toss out a kiddo’s uneaten goldfish crackers. The fact that they’re dishwasher safe is a bonus.

Recline Positions

The seat has 9 recline positions. They’re numbered 1-8 for the rear and forward facing harness modes, and B for booster mode. The recline mechanism is easy to adjust — just press one of the buttons on either side of the car seat and slide the shell to the desired position. The positions are labelled using white on red, and the black base has a small window that shows which recline position the seat is in. We found this design is very easy to read, so we give it an enthusiastic thumbs up!

Color-Coded Recline Angle Guide

Britax One4Life recline indicator

The One4Life’s recline angle indicator is quite easy to read. There’s an indicator on both sides of the seat so it’s always visible. In addition, there’s a large, comprehensive label with a guide to the proper recline angles on the side of the seat near the indicator so it’s easy to determine if the seat is installed at the right angle for your kiddo.

Note: the booster mode position is labeled “B,” while the recline angles for harness modes are numbered.

Soft Goods Special Features

Britax One4Life cover mesh panels

  • Mesh panels – on either side, allows for better ventilation for the child
Britax One4Life harness covers

Britax One4Life harness covers

  • Stay-Put comfort pads – the comfort pads on the harness are connected by a strap so they don’t fall down or end up out of place. We found that this part made the harness pads sit up really high on my models, right on the sides of their necks, but none of our models complained about the placement.

Britax One4Life belly pad

  • Flip-Forward crotch buckle/belly pad – this latest version of Britax’s crotch buckle cover means no more digging for that crotch buckle under the kiddo. The crotch buckle flips forward when the child isn’t in this seat so it’s out of the way when the child is loaded into the seat.
  • Removable cover — the Drift fabric on our review seat is one of the options in the SafeWash line of fabrics. The only One4Life fashion that is not outfitted with a SafeWash cover is Black Diamond.

Energy Management

Britax One4Life SafeCell

Britax One4Life SafeCellB

The One4Life includes a steel frame, EPS foam, and SafeCell technology. While none of these features are required as part of the FVMSS213/CMVSS213 federal safety standards, Britax has a long history of working to exceed those requirements in as many ways as possible.SafeCell is the red honeycomb-like plastic on the sides of the seat. It is designed to act as a crumple zone during a crash.

V-Shaped VersaTether

Britax One4Life VersaTether

The top tether is a crucial part of your child’s car seat. It reduces the risk of head excursion by 4-6 inches in a crash (and it legally required to be used on all forward facing harnessed seats in Canada). Britax uses a V-shaped tether that works a little differently than the single strap most other manufacturers use — it usually needs to be routed around the vehicle headrest.

The top tether and lower anchors can be used in booster mode. When it’s not in use, the tether stores on a loop right on the back of the seat. Even better, the tether comes with a band so the excess tether strap can be wound up.

Smooth Shell

Britax One4Life base

The One4Life has a smooth and flat base, without any protrusions or sharp angles that could damage the vehicle seat. That smooth base can also help with some installations. The base also has an added feature, a notch cleverly designed to fit a pool noodle!

If needed, a pool noodle may be in recline setting 1 only to install the seat at the proper recline angle for a newborn.

Carry Handle

Britax One4Life handle

Britax One4Life handle

The addition of a handle at the top of the seat makes picking up the One4Life a bit easier. It is a heavy seat, so having something to hold onto is a very nifty perk.

Standard J-hook Lower Anchor Connectors

Britax Click Tight convertible lower anchor connectors

The One4Life installs quite easily with the vehicle seat belt, but because lower anchors are federally mandated, they are included with the seat. The One4Life now includes standard j-hook lower anchor connectors like the ones pictured here. We’d suggest attempting the installation with the vehicle seat belt first before even removing those lower anchors from the storage pouch under the cover of the seat.

Britax One4Life premium lower anchors

Note: early versions of the US One4Life featured premium lower anchors, but newer US seats and the Canadian version feature standard J-hook style lower anchors.

Lower Anchor Weight Limits

The One4Life’s lower anchor weight limits are pretty low: 30 pounds for rear facing and 35 pounds for forward facing. That’s because the One4Life weighs in at a pretty hefty 30 pounds. Of course, the seat can always be installed with a vehicle seat belt as long as the child is within the weight limit for the seat.


Manual Highlights

Airplane Installation Instructions

Britax One4Life airplane installation instructions

Britax One4Life airplane installation instructions

Britax has placed detailed instructions for installing the One4Life on an airplane at the very front of the manual, just after a large aircraft certification notice. General instructions and helpful tips follow just after that. We recommend that parents bring a copy of their car seat’s manual with them when flying, so it’s really convenient to have these instructions right in the front, on pages 6 and 7. We’d also like to note that the One4Life is pretty heavy so travelling with it might not always be the most feasible option. However, the ease of installation may make the challenge of travelling with such a heavy seat worthwhile.

Color Coded Manual and Belt Paths

Britax One4Life ClickTight panel

Britax One4Life ClickTight panel

The One4Life’s manual has color coded rear facing, forward facing, and booster mode instructions to match the manual; blue for rear facing, green for forward facing, and red for booster mode. Even the features page (which details the parts of the seat) uses these colors to indicate the parts of the seat that are used specifically for those three modes of use.

Cleaning Instructions

Britax One4Life cleaning instructions

Britax One4Life cleaning instructions

The manual has cleaning instructions broken down into four sections: the shell, the cover, the harness, and the harness buckle.

Included are a column of cleaning instructions, side by side with red warnings. This level of detail should be helpful to caregivers when it’s time to clean the car seat.

Plush Cover

The One4Life is padded, soft, and cushiony, however I did feel that the placement of the mesh side portions seemed a bit awkward because they seemed to want to fold inwards. We suspect that the padding would settle into place nicely once the seat isn’t so brand-new. I found that the cover pops off in the front, where the seat meets the vehicle seat back, and also at the top of the headrest. This was a mild annoyance on a seat that’s otherwise pretty awesome.


Installation – Rear Facing

Britax One4Life rear facing

Britax One4Life rear facing

Setup: Installing the Anti-rebound Bar

One4Life anti rebound bar

Britax One4Life anti-rebound bar

In Canada, the anti-rebound bar must be used at all times when using the Britax One4Life rear facing (the Anti Rebound Bar is optional for users in the United States).
The anti-rebound bar is quite easy to install:

  • Open the ClickTight panel
  • Insert the anti-rebound bar into the two openings at the front of the seat
  • Attach the elastic bands from the cover to the hooks on the shell
  • Pull the anti-rebound bar to ensure it is connected


Installing the One4Life with the ClickTight locking system is just about the easiest installation that we’ve attempted.

First, set the One4Life on the vehicle seat with the harness facing the back of the vehicle. Adjust the recline angle to the correct position for your child.

Then, remove the elastic loops from the top of the cover (at the part of the seat where the child’s legs would be), then open the ClickTight panel by pinching the red tabs. The ClickTight panel will rise up to expose a very easy-to-see belt path! Next, thread the vehicle seat belt or lower anchor belt through the rear facing belt path (well marked and labelled with a blue label), remove most of the slack from the seat belt or the webbing, then close the ClickTight panel. Done! Check for movement at the belt path — give the seat a firm handshake with your non-dominant hand and confirm that there’s less than an inch of movement at the belt path.

Fit to Child – Rear Facing

18 Days Old

One4Life newborn

One4Life newborn

We were lucky to have a neighborhood baby born while writing this review, so we were able to “borrow” him (and his brothers) to model for us. This little guy is 18 days old, weighs 11 pounds, and is 21 inches tall. We were able to move the headrest to the 2nd position from the bottom and still have the harness placed below his shoulders, which was great!

Because this model is in Canada, the lower infant insert is required until 22 pounds. The padding made it a bit difficult to get him situated nicely, which was unfortunate since the harness fits him so nicely. We ended up moving the crotch buckle to the middle slot, and even then it was quite short on our model. We can see how the crotch buckle length may be an issue for older kiddos in Canada who are under 22 pounds, as it takes up quite a bit of the crotch buckle webbing length.


One Year Old

Britax One4Life toddler

Britax One4Life toddler

Our 1 year old model weighs 22 pounds and is a petite 28 inches tall. She has a lot of room left to use the One4Life in rear facing mode. While she is petite, she also has a pretty bulky cloth diaper on, which takes up some space between her and the crotch buckle strap. The strap is under her diaper a bit, but it is not under her body.

Two Years Old

Britax One4Life toddler

Britax One4Life toddler

This 2 year old weighs 32 pounds and is 35 inches tall. She’s got plenty of room to continue rear facing in this seat. She’s got plenty of harness height left to grow and had a lot of legroom even though she is in the US and the anti rebound bar is not in use. She giggled and smiled for me while she modelled this seat — she was pleased to be bucked up and was comfortable. The One4Life was so comfortable that she fell right asleep in it, not just once but twice!

Two Years Old

Britax One4Life 2 year old

Britax One4Life 2 year old

Our second 2 year old model weighs 29 pounds and also is 35 inches tall. We can see that he has a much longer torso than our other 35 inch model, and although the photo angle doesn’t show it, he has just over one inch of shell over his head in the One4Life. The additional padding has been removed (as required) and he fits the seat quite well.

Installation – Forward Facing

Britax One4Life forward facing

Forward facing installation was just as easy as rear facing installation using the ClickTight mechanism.

First, undo the tether from its storage spot on the back of the seat, and clip it to the tether anchor in your vehicle. Because it improves safety significantly, we always recommend using the tether for a forward facing seat. In Canada, the top tether is legally required.

Next, make sure that the recline position selected allows the arrow in the recline angle indicator to sit in the green section.

For the actual installation, this is the easy bit, open the ClickTight panel, place the vehicle seat belt in the forward facing belt path – indicated with green labels – buckle the seat belt, and close the panel. Lastly, tighten the tether. It really is that easy!

In many vehicles we were able to install the seat at a deep recline angle in forward facing mode. This option could be great for special situations, such as for kids with special needs or even when parents just prefer a deeper recline for their little ones.

Fit to Child – Forward Facing

Three Years Old

Britax One4Life preschooler

Britax One4Life Three Year Old

Our 3 year old model weighs 30 pounds and 38 inches tall. He was happy to show us the great harness fit that the One4Life offered him and he seemed really comfortable in the seat. The harness pads connect through the cover at the back, but they seemed a bit short on him. I think this kiddo would probably prefer longer harness pads for comfort.

He found it a bit difficult to climb into the seat on his own, but I got him in and buckled up fairly easily. Since Britax has given the One4Life a terrific 19 inch top harness position, we have no doubt that the One4Life will accommodate this kiddo in harness mode until he reaches a safe booster age.

Five Years Old

Britax One4Life 5 year old

Britax One4Life 5 year old

Our first five year old model is a veteran car seat tester for Car Seats for the Littles. She has been featured in many of our Canadian reviews, and does not hesitate to let us know her thoughts on the different seats she has tried. She recently had a growth spurt and now stand 46 inches tall and weighs 43 pounds.

Despite her disdain for harness covers, our model did not once complain about the harness covers on the One4Life. After a few drives she also asked “can I keep this seat forever?”, so it must be quite comfortable! We have left the crotch buckle padding and harness padding on this model and the seat fits her quite nicely with the harness in the second-highest position.

Five Years Old

One4Life 5 year old

One4Life 5 year old

Our second 5 year old model is right at the harness weight limit for the One4Life. He weighs just under 65 pounds and is 47 inches tall. Although he rides in a booster full time with his parents, he agreed to test out the One4Life’s harness for us (possibly after a bribe).

One4Life 5 year old

One4Life 5 year old

We were quite impressed at the amount of room he had in the One4Life above his shoulders. The 49 inch height limit and 19 in top harness position mean that the One4Life should be able to accommodate most (if not all) children to one of the stated limits (49 inches tall or 65 pounds). With the harness in the top position, this kiddo has about 1.5-2 inches of growing room before he hits the forward facing torso height limit, where the harness is no longer above his shoulders.

We did, unfortunately, run into some fit issues with the crotch buckle again for this model. Buckling him in was a bit awkward, and he expressed that he was not especially comfortable in the harness of the One4Life due to the crotch buckle length.

Converting to Booster Mode

To convert the One4Life to booster mode:

  • Unbuckle the chest clip and crotch buckle, raise the headrest all the way up, and loosen the harness all the way
  • Flip up the headrest cover and position the harness straps behind the seat pan cover
  • Fold the top of the seat pan cover with the vented side over. Position the harness straps behind the seat pan cover.
Moving the chest clip for booster conversion on the Britax One4Life

Moving the chest clip for booster conversion on the Britax One4Life

Fasten the chest clip and move it to the middle of the back rest.

Covering the buckle tongues with the harness covers of the Britax One4Life

Covering the buckle tongues with the harness covers of the Britax One4Life

Remove the harness covers and re-attach them to the harness, covering the buckle tongues. Slide the harness covers (and buckle tongues) to the middle of the back rest (with the chest clip)

Harness, chest clip, and buckle tongues tucked into the seat back of the Britax One4Life

Harness, chest clip, and buckle tongues tucked into the seat back of the Britax One4Life

Locate the space in between the back of the shell and the back-top part of the seat pan and tuck the chest clip and harness covers in the gap with the excess harness webbing (ensuring the harness webbing lies flat)

Removing the crotch buckle of the Britax One4Life

Removing the crotch buckle of the Britax One4Life

Open the ClickTight panel and remove the crotch buckle from the seat.

Storing the crotch buckle for booster mode of the Britax One4Life

Storing the crotch buckle for booster mode of the Britax One4Life

Place the buckle horizontally on top of the raised section of the seat shell (in the center) that guides the harness adjuster strap.

  • Roll the remaining harness adjuster strap and tuck it into the cover
Close the ClickTight panel and flip the headrest cover back down

LATCH/LUAS in Booster Mode

Britax One4Life lower anchors in booster mode

The lower anchor connectors and tether may be used in booster mode to secure the One4Life when it is not being used so that it does not need to be buckled in when there is no child riding in it.

Booster Mode

Britax One4Life in booster mode

Britax One4Life in booster mode

Here’s the One4Life converted to booster mode, ready to go! We were pleasantly surprised at how well it fit our wide range of models, from the youngest and smallest to the oldest and tallest.

Fit to Child

When the One4Life was in booster mode for the smallest of booster riders, we did find that the vehicle seat belt retracted slowly because the headrest had to be down fairly far in the shell in order to provide a good belt fit. This is par for the course for many multimode and combination car seats in booster mode. We’d typically suggest that caregivers facing this issue return the child to harnessed mode until they’re tall enough that the shoulder belt guide is taller than the seat’s shell.

Five Years Old

One4Life - 5 years old

One4Life – 5 years old

Our first 5 year old model remains 43 pounds and 46 inches tall. Though she meets the minimum height and weight requirements to ride in a booster seat, she is not quite yet booster ready so she tested the One4Life for us in the driveway only.

The vehicle seat belt fit her beautifully – the lap belt is low on her hips, touching her thighs, and the shoulder belt is centered on her shoulder.

Five Years Old

Our second 5 year old model remains 65 pounds and 47 inches tall. We see another beautiful seat belt fit provided by the One4Life.

One4Life 5 years old

One4Life 5 years old

One4Life 5 year old

One4Life 5 year old

We raised the headrest to the highest position to see how much growing room this model has in the One4Life’s booster mode, and with an average torso growth of 1-1.5 inches per year, we think it’s safe to say that the One4Life should be able to accommodate him for another 3 years or so – which is a long time for a multimode seat!

Because this model is a newer booster rider, he found the deep sides of the One4Life meant that he required adult assistance to buckle up – but we were happy to help him!

Seven Years Old

One4Life 7 years old

One4Life 7 years old

Our 7 year old model is 53 inches tall and weighs 61 pounds. We have raised the headrest to the highest position for her, she looks to have about 2 inches of torso growth before the shoulder belt is no longer above her shoulder. That should pretty easily get this model to 8 years old, which is again pretty great for a multimode seat!

She was able to buckle herself in without any help (as she is a veteran booster rider) and she found the One4Life quite comfortable.

Important Information: Where to Find

Britax One4Life manual storage

Manual storage: the manual storage pouch is on the inside of the cover. This storage spot is marked on the front of the cover with a small tag.

One4Life National Safety Mark

One4Life National Safety Mark

National Safety Mark (Canadian Users): the NSM is located on the child’s left side of the seat, below the forward facing belt path

Britax One4Life date of manufacture label

Britax One4Life date of manufacture label

Date of manufacture/expiration label: this is found just under the seat’s cover on the ClickTight panel on the child’s left hand side. The date of manufacture and expiration date are both listed on this label.

Britax One4Life label

FAA approval label: the One4Life is approved for use on aircraft in harness mode only, and this notice is in the manual but is also on the sides of the seat, on the information label.

Since the seat is so heavy, we can’t see many families choosing this seat for travel, though we can see how the easy ClickTight installation might tip the scales and encourage some families to travel with this seat. Our Editorial Director took a Frontier on many an airplane trip when her kids needed a harnessed car seat — that easy installation made the effort totally worthwhile!


Overall Thoughts

Installing the One4Life is about is as easy as installing a car seat can be. We list this first because if the seat is easy to install, there’s a higher likelihood that the seat will be installed and used correctly.

We found the One4Life versatile and long-lasting. While many newborns in the US won’t fit the seat at birth (in Canada the fit shouldn’t be an issue), the One4Life’s 50 pound rear facing weight limit and tall shell will allow children to ride rear facing for a very long time. The 19 inch tall top harness position makes the One4Life one of the longest lasting harnessed car seats by seated height. Our biggest concern is that some children may find that the harness is outgrown earlier than the stated limits due to discomfort at the length of the crotch buckle. We’d love to see Britax make a longer crotch buckle available – especially for Canadian users.

The One4Life is a terrific addition to Britax’s car seat lineup. It has a lot to offer in all modes and the ease of installation just can’t be beat.


To celebrate the release of the Britax One4Life to the Canadian market, Britax is giving away one One4Life to a lucky Canadian reader. Our terms & conditions can be found here. Enter the giveaway below!

a Rafflecopter giveaway

Originally written by Laurel, edits maintained by CSFTL.