The Britax One4Life All-In-One Car Seat is exactly as it sounds-one car seat to last your child through their car seat-using years. 

This convertible car seat grows with your child from 5-120 pounds until they no longer need a protective seat while riding in the car. This convenient convertible seat becomes three seats. 

Main Advantages 

First, the chair is a rear-facing infant car seat. Use it to bring your new baby home from the hospital up until they are 50 pounds. 

Once your child outgrows the car seat, the chair transitions to a forward-facing 5-point harness seat. Finally, your older child can use the chair as a high-back belt-positioning booster seat until they are 120 pounds.

Drawback: No Backless Booster 

This convertible seat does not `have an option for a backless booster seat. These features claim to give you ten years out of one seat, as the average child does not reach 120 pounds until they are around ten-years-old.

In order to fit a quickly growing child, the Britax One4Life has a 15-position, quick-adjust headrest, and harness, as well as a quick-push, 9-position recline. 

These features combined allow your child to be safe and comfortable, no matter their height or weight combination. Even though this Britax Car Seat has numerous features and contraptions, it is still designed with comfort in mind for your little one. 

The seat has built-in cooling channels and ventilated mesh to improve airflow and keep your child cool and comfortable. Dishwasher-safe cup holders keep drinks and snacks within an arm’s reach, and a removable head pillow is an added comfort to the ride.


  • Users rave about how soft and comfortable the padding is
  • Installation is quick and easy
  • Easy to clean
  • Easy-to-follow instruction manual
  • Cup holders allow for drinks and snacks for your child and are dishwasher safe 
  • The base is solid and flat, so does not leave any indentations in the seats of your car
  • Infant insert prevents infant head from drooping to sides during the ride
  • Easy to convert between children of different ages and sizes
  • The harness can be fastened and unfastened with one hand


  • The seat is very large and takes up a lot of space
  • May not be ideal for smaller cars or families that need multiple car seats.
  • Straps can be difficult to tighten, and chest clip seems to dig into baby’s chest 
  • Heavy and difficult to carry.

Key Features

  • Convertible: from rear-facing infant seat to forward-facing harness seat to high-back booster seat
  • Built-in cooling channels and ventilated mesh: improve airflow for comfort
  • 5-Point safety harness: with diamond-weave webbing
  • Dishwasher-safe cupholders: easily removable for hassle-free cleaning
  • 15-Position, quick-adjust headrest, and harness: grows with your child for optimum comfort and safety
  • Removable cover: for easy cleaning
  • Aircraft use: certified for aircraft use in harness mode only


  • Product Weight: 30 lbs
  • Product Dimensions: 20.5” (L) x 19.5” (W) x 25” (H)
  • Rear-Facing Harnessed Weight: 5-50 lbs.
  • Rear-Facing Harnessed Height: Less than 49”
  • Forward-facing Harnessed Weight: 22-65 lbs.
  • Forward-facing Harnessed Height: Less than 49”
  • Belt-Positioning Booster Weight: 40-120 lbs.
  • Belt-Positioning Booster Height: 44-63”

Safety Ratings

The Britax One4Life ClickTight Convertible Car Seat meets or exceeds all of the NHTSA Federal Safety Standards. In addition to the requirements, this seat also has the following additional safety features:

  • ClickTight Installation: three easy steps to help you install perfectly every time.
    • Pinch to open
    • Thread and buckle
    • Click to close
  • High Strength Steel Frame: reinforces the structure of the seat and helps keep your child secure and stabilized in the event of a crash.
  • SafeCell Technology: acts as a crumple zone that keeps crash energy away from your child in the event of a collision.
  • Two layers of Side Impact Protection: energy-absorbing shell and foam lining protect your child’s head, neck, and torso. 
  • V-Shaped Tether: releases slowly to reduce forward movement during a crash.


The Britax One4Life ClickTight All-in-One Car Seat has a one-year warranty against defective materials or workmanship with proof of purchase.  Defective parts will be adequately replaced or repaired.


The Britax One4Life Car Seat has an expiration of ten years from the date of manufacture.  The manufacture date will be clearly posted by the serial number on a label on the base of the car seat. 

Honest Customer Reviews

It’s no surprise that the Britax One4Life ranks highly among customers.  Reviewers typically have nothing but positive things to say about this seat.

Comparing Britax One4Life to Similar Car Seats

Graco 4Ever 4-in-1 Convertible Car Seat

These two seats are similar in many ways. The first is that they both last for ten years, and grow with your child up to 120 pounds. Both car seats have similar weight conversions and are easily adjustable to fit your child. Graco 4Ever 4-in-1, in addition to being slightly less expensive, is also lighter by almost 8 pounds.


  • Multiple seat options that adjust for up to ten years of use for your child
  • Covers can be removed easily for cleaning and are machine washable
  • Dual cup holders


  • Graco’s frame is steel-reinforced, while Britax’s frame is made entirely of steel
  • Graco 4Ever is about 8 pounds lighter than the Britax One4Life
  • Britax One4Life offers more adjustment positions on both the headrest and recline
  • Britax is more expensive, but also offers more safety features
  • Graco 4Ever can convert to one more type of seat-the backless booster

Chicco MyFit Harness Booster Car Seat

The Chicco KidFit Harness Booster Car Seat is a convertible car seat that offers some of the features of the Britax One4Life but does not have as many convertible options or last for a full ten years. 

The Chicco MyFit grows with your child from 25-100 pounds. It does not serve as an infant car seat but serves your toddler and big kid for many years. The Chicco MyFit is a great convertible seat choice for a family that already has a car seat.


  • Both seats have soft padding to keep your child comfortable and safe
  • Easy installation using seatbelt or LATCH technology
  • Detachable, dishwasher-safe double cup holders
  • 5-point, easy-adjust harness
  • Bubble Level Indicators
  • Both chairs have armrests to enhance the comfort of your child’s ride


  • Britax One4Life starts as an infant car seat and lasts for up to 120 pounds, while the Chicco MyFit starts as a toddler seat and lasts for up to 100 pounds.
  • The Chicco MyFit is about five pounds lighter than the Britax One4Life.
  • Cup holders in the Chicco MyFit are foldable for when they are not being used.
  • Chicco MyFit’s frame is steel-reinforced, while Britax’s frame is made entirely of steel.
  • Chicco MyFit is considerably cheaper; however, it does not serve your child for as long.

Diono Radian 3RXT Convertible Car Seat

Both the Britax One4Life and the Diono Radian Car Seats are top-of-the-line convertible car seats. They both offer many additional safety features that go above and beyond the basic safety requirements for infant and child car seats. Both seats are approved for use for children from 5-120 pounds so that they will last your child for a decade.


  • Removable, machine-washable covers.
  • Soft fabric with extra padding for comfort and safety.
  • Easy installation with LATCH system or seat belt.
  • Both seats have a full steel frame.
  • Multiple adjustments for both the headrest and recline position to accommodate your child. 


  • The Diono Radian has expandable leg rests and a memory foam seat for added comfort.
  • The Diono Radian does not offer cup holders.
  • The Britax One4Life is only slightly heavier, by about two pounds.
  • The Diono Radian is a more narrow fit in your car so that you can fit multiple in your backseat. Users complain of the Britax One4Life’s size and that it does not easily fit multiples in your car.

Car Seat for Life

Customers provide numerous positive reviews that rave about how pleased they are with their purchase because of the ease of use and safety of this seat. Although it is somewhat large and heavy for a car seat, it has a solid steel frame for the utmost safety.

The soft fabric, ample padding, and dual cup holders make this seat a comfortable choice for your child, no matter how long the ride.  The Britax One4Life ClickTight All-In-One Car Seat is a fantastic option for families who want one chair to last from infant to big kid.


Welcome to my car seat blog! As a mom of 3, I put together with other hard-working moms a highly informative one-stop car seat resource, full with many reviews and buyer guides. I hope you find it invaluable. Thank you for trusting me & my team! - Keren

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