Evenflo Big Kid/Amp Review

(Last Updated On: )

Looking for an inexpensive or lightweight booster seat, or a narrow option for a tight space? The Evenflo Big Kid Amp may be for you! These boosters are sold as high back or backless boosters. There are a few flavors of trim and features for this seat, we’ll look at the Amp in this review.

We’ve got an updated review of the Big Kid Sport in addition to this older review.

CSFTL Quick Stats

  • High back booster weight range, United States: 40-100 pounds.  Note: the 2013 version of the seat used in this review had a lower minimum weight.  We’re pleased to see the higher minimum weight on seats sold today and reiterate our recommendation that children be at least 5 years old before moving to a booster seat.
  • High back booster weight range, Canada: 40-100 pounds
  • High back booster height range: 38-57 inches tall
  • Backless booster weight range: 40-110 pounds
  • Backless booster height range: 40-57 inches tall
  • Highest booster guide position: 19 inches
  • Width at widest point (at the elastic cupholders): 16 inches
  • Expiration: 6 years
  • IIHS Best Bet in backless mode
  • Vehicle headrest required for backless mode only


Headrest Adjustment

Evenflo Big Kid, hbb, nbb, booster, Amp, Big Kid Sport

Evenflo Big Kid head rest adjustment

All models adjust easily by squeezing the handle on the back of the top of the headrest. The tallest of the six headrest positions is approximately 18.5″. You can use the back until the child’s shoulders go over the belt guide in the highest adjusted position. The seat converts to backless mode and is sold separately as a backless booster.

The Big Kid/Amp only require a vehicle headrest behind them when used in backless mode. The seat can be used backless until the upper weight limit, 57″, or the tops of the child’s ears are over the seat back or headrest. The seat does come with a seatbelt adjuster as well to help obtain proper fit when used in backless mode.

Fit to Child

High Back Mode

5 Years Old

Evenflo Big Kid Amp: 5 years, 7 months old, 48 pounds, 46 inches tall

Evenflo Big Kid Amp: 5 years, 7 months old, 48 pounds, 46 inches tall

This model is 5 years old.  She’s barely at the minimum age and maturity level to ride in a booster.  The Amp fits her well — the shoulder belt lies across the middle of her shoulder and the lap belt fits across the tops of her thighs.  She was able to buckle herself in without too much trouble.

9 Years Old

Evenflo Big Kid 9 years old, 58 pounds, 51 inches tall

Evenflo Big Kid 9 years old, 58 pounds, 51 inches tall

This model is 9 years old.  She’s at the top of the height limit in high back mode but still has a bit of room to grow.

Fit to Child

Backless Mode

6 Years Old

Evenflo Big Kid, hbb, nbb, booster, Amp, Big Kid Sport, Huggable Images

Evenflo Big Kid, backless- Chloe, 6 yrs., 46 pounds., 48 inches

This 6 year old Huggable Images doll is 48 inches and 46 pounds.  The Evenflo Amp fits her well. The Amp does come with a seat belt adjuster guide, but even without using it, seat belt offers a proper fit.

8 Years Old

Evenflo Amp backless mode 8 years old

Evenflo Amp backless mode 8 years old

Our 8 year old model weighs 53 pounds and is 49 inches tall.  The Amp offers him the same excellent belt fit that we see on our other models.  This type of consistent belt fit makes the Amp an excellent option!


Evenflo Amp, Evenflo Big Kid, nbb, hbb, improper use, sleeping in booster, booster

Dangerous booster use while sleeping in an Evenflo Big Kid

Body slump while sleeping was the biggest downfall of this seat for our 6 year old car sleeper. This is clearly unsafe and improper use. She was able to sit and sleep properly when a forward facing car seat was next to her, but when it was replaced with a rear facing car seat, this started to happen. She had to use a different booster seat with more support for her head and torso to keep her upright when she fell asleep.

Three Car Seats Across

Evenflo Rightfit, Right Fit, backless booster, booster, hbb, nbb, Big Kid, Radian

Evenflo RightFit, Diono RadianRXT, Evenflo Big Kid

The Evenflo Big Kid/Amp worked great in three car seats across situations with quite a few different seats in our Town and Country minivan. The Amp didn’t have the vehicle seat belt retraction issues that seem to plague the Town and Country’s third row. The belt retracted smoothly and maintained its position flat against the child’s chest.

This is the Evenflo RightFit, Diono RadianXT, and Evenflo Big Kid LX in the third row of a 2007 Town and Country.

Important Information: Where to Find

Evenflo Big Kid/Amp expiration sticker and manual storage

Evenflo Big Kid/Amp expiration sticker and manual storage

Expiration  The Evenflo Big Kid/Amp has a 6 year expiration. If you turn the booster over, you will see the sticker containing the date of manufacture, model name, and expiration date, as well as the manual storage area.


Manual Storage  The manual is stored on the bottom of the seat as shown in the picture to the left. This is helpful as you will always have the manual available when needed.


FAA Approval  This seat is not FAA approved, but because of it’s more compact size, it would work well as a carry on for the child to use at their final destination.


  • Inexpensive
  • Does not require vehicle head support
  • Converts to backless


  • Not much head/torso support
  • No lower anchors

Overall Thoughts

The most important part of using a booster seat is that the child is mature enough to sit properly for the entire ride, and that the belt fits properly. A good booster fit positions the shoulder belt even across the torso – not sliding off the shoulder or cutting into the face; the lap belt should be low on the hips, touching the tops of the thighs.


The Evenflo AMP High Back Booster and Evenflo Amp No Back Booster  versions are available on Amazon.com. It features built-in elastic cup holders and non-movable arms. The Big Kid Sport is similar to the Amp and is available at Wal-Mart.




ev-353_1zThe Evenflo Big Kid LX is only available in high back, but does convert to a backless booster. It features pull out cup holders on each side and flip-up arms. My kids found no difference in the ability to buckle themselves in with either type of armrest.



evenflorightfitThe Evenflo RightFit Booster  is a slight variation of the Amp. It has the same bottom footprint, but much more sizable headrest and torso padding.


Neither Evenflo nor Amazon sponsored this review; as always, the opinions expressed are all mine!