When can DD go into a booster


New member
My dd is 3 yr and 3 months in a britax MA and is constantly complaining that she is not good and is uncomfortable. When can she go into a booster?


CPST and ketchup snob
Staff member
Ideally, not for another 2 1/2 to 3 years. :)

Kids need to be at a bare minimum 4 years old, 40 lbs., have the belt positioned properly, and sit properly the entire ride to use a booster.

Most kids gain that maturity more toward 5 1/2 or 6 years than 4, really.

If she is uncomfortable, moving to a different harnessed seat may help. Where are the straps coming from in relation to her shoulders- above or below? How much does she weigh? We can help you troubleshoot what may be causing her discomfort.


CPST and ketchup snob
Staff member
It may be that the straps are squishing her down a bit. You can try moving them up a bit (if she is forward facing, as I'm assuming.) Also, make sure that the crotch strap is in the position closest to but not under her body, and scootch her all the way back before you buckle her.

At 28 lbs., she could actually still be rear-facing if she fits by height. Some kids are more comfortable that way because they can lie back more.

She's so light she'll need a harnessed seat for a long time, since 40 lbs. is one of the requirements for most kids to safely use a booster. Kids under 40 lbs. are at an increased risk of flipping under the belt, or "submarining," in a crash.

How does she sit in the seat? When does she complain, specifically? When she wants to reach something and can't? When you buckle her in? When you tighten the straps?

I would also recommend that you might want to consult with a technician in your area in person, to help you spot and solve problems. This thread has a list of techs on the board, and a link to the website to find one if none are listed in your area.


New member
My DD is 3.5 yo. We recently moved her from her Marathon to a Frontier for her main seat. The Marathon was so reclined in our car (almost more than it had been when she was RF - she only started FF around 3y2m). The Frontier is more spacious and more upright. It also doesn't sit up as high which is nice for her as she gets older, but she can't see out the windows as well.

The MA only has one crotch strap position, but make sure the straps are coming from above her shoulders. And make sure the harness covers are in a good spot. When we turned my DD FF I pinch her neck much easier when tightening the straps.



Carseat Crankypants
At 28# and barely 3y, she cannot legally use a booster.

Best practice is to keep children harnessed until 4y and 40#, and then begin booster training. Most of us don't like to see full-time booster use until about 5y.

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