Britax One4Life Review

(Last Updated On: March 8, 2021)
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 and Boulevard, the forward facing combination car seat, the Grows With You, and now it’s an integral part of Britax’s newest offering — the One4Life.

This plush, long-lasting 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 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: until the child’s head is 1 inch below the top of the headrest
  • 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


  • Crotch buckle positions: 4, 6, and 7.5 inches from the back of the seat pan
  • Lowest harness position: 9 inches (with 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

Unique Features

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.  I 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

Britax One4Life insert limits

This insert very clearly states that it is for use with children who weigh less than 20 pounds. This sounds like a small thing — printing an insert’s height and weight limits on the insert itself — but we find time after time that caregivers don’t refer to the manual for this kind of information and end up using the inserts way too long.  Having such large numerals right there on the insert will no doubt help caregivers know when to remove the insert as their child grows.

Headrest Cover

Britax One4Life cover folded up

The headrest cover must also be unfolded when the seat is used for children who weigh more than 20 pounds. That’s a little hard to explain, hopefully our photo says it best!

Britax One4Life Cover Adjustment

The inside of the cover has some thoughtfully placed velcro squares that keep the cover in place when the headrest is folded.  That velcro 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. I appreciated being able to take a cupholder right off the seat to toss out my 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 move 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 labelled “B,” and the recline angles 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. I found that this part made the harness pads sit up really high on my models, right on the sides of their necks, but no one 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

The One4Life includes a steel frame, EPS foam, and SafeCell technology. While none of these features are required as part of the FVMSS213 federal safety standard, 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.  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! A pool noodle may be used to further recline the seat, in recline setting 1 only, in order to achieve a the proper recline 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.

Premium Lower Anchor Connectors

Britax One4Life premium lower anchors

The One4Life installs quite easily with the vehicle seat belt, but it does include premium lower anchor connectors as well.  We’d suggest attempting the installation with the vehicle seat belt first before even removing those lower anchors from their handy storage compartment.

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.


Lower Anchor Storage

Britax One4Life lower anchor storage

When they’re not in use, the lower anchor connectors clip into a storage spot inside the ClickTight compartment.  They even have their own little storage bag in that compartment!

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 really 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

Installing the One4Life with the ClickTight locking system is as easy as can be. 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 compartment 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 compartment. 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.

Newborn Recline

We found that on some recessed vehicle seats, we needed a rolled towel or pool noodle to get the type of deep recline that a newborn or baby who lacks neck control would need. It is so helpful that Britax added a notch right in the base for a pool noodle!

Fit to Child – Rear Facing

Newborn Doll

Britax One4Life newborn doll

Britax One4Life newborn doll

This Huggable Images newborn sized doll weighs 7 pounds and is 17 inches long.  The doll fits snugly in the One4Life, however the harness rests just above its shoulders. All of the padding is very supportive and the harness fit elsewhere was superb.

Britax One4Life newborn doll

Britax One4Life newborn doll

The bottom harness position is 9 inches from the bottom of the seat pan. Since the average newborn torso is around 7-7.5 inches, the One4Life may not fit newborns well since the harness must be placed at or below the child’s shoulders. However, the bottom harness position seemed to be only within a month or two of growth away.

1 Year Old

Britax One4Life toddler

Britax One4Life toddler

Our 1 year old model weighs 22 pounds and is a petite 28 inches tall.  She’s got 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.

One thing we’ve heard about some of the other Britax convertible seats is that the crotch buckle strap is shorter than they’d like.  We’re pleased to see that the One4Life’s crotch buckle strap is plenty long for this kiddo.

2 Years Old

Britax One4Life toddler

Britax One4Life toddler

This 2 year old weighs 32 pounds and is 25 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.  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!

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. Next, make sure that the recline selected allows the arrow in the recline guide to sit in the green section. Lastly, and this is the easy bit, open the ClickTight compartment, place the belt in the forward facing belt path – indicated with green labels – buckle the belt, and close the compartment. Lastly, tighten the tether. It really is that easy!

In my Dodge Durango, I was 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

3 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.

Converting to Booster Mode

Britax One4Life harness storage

To convert the One4Life to booster mode, raise the headrest all the way up and lift the cover and you’ll find a large label that says Harness Storage Compartment. You guessed it, this is where the harness stores!  Pinch the tabs to open the door and expose a generously large storage compartment. The label inside the compartment door shows the correct order to store the crotch buckle, chest clip, and harness. This small touch can make a big difference in terms of using the seat properly!

Britax One4Life harness stored for booster mode

Follow the directions in the manual to move the harness into this compartment and prepare the seat for booster mode. Note: the harness pads and buckle pad do not go in this storage spot, so keep them in a safe location.

LATCH 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 booster mode

Britax One4Life 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 really 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.

We tested the One4Life in booster mode with a 7, 9, and 12 year old.  We found that it fit those models well and they felt that the seat was quite comfortable.  They were all able to buckle themselves in without issue and we were pleasantly surprised to discover that it fit all of those models.


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.

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 compartment 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.


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 won’t fit the seat at birth, 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.

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

Originally written by Laurel, edits maintained by CSFTL.