Booster Seats vs Car Seats With Harness Straps

Baby in car seat.
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There are many belt-positioning booster seats with minimum weight limits of 30 to 33 pounds, but the American Academy of Pediatrics has long said that 'your child should stay in a car safety seat with a harness as long as possible before being allowed to ride in a booster seat.'

And since there are many convertible seats and combination seats that allow you to use harness straps up until your child is 40 pounds or more (the Britax Marathon can be used up to 65 pounds with a harness), you could keep your child in a car seat with a harness strap a little longer with one of these seats.

When to Switch to a Booster Seat

In general, the AAP states that "Booster seats are for older children who have outgrown their forward-facing seats." But since they also state that children "should use a forward-facing seat with a harness for as long as possible, up to the highest weight or height allowed by their car safety seat manufacturer," they aren't encouraging an early switch to a booster seat.

The CDC recommends that children ride in a forward-facing car seat "until at least age 5 or when they reach the upper weight or height limit of their particular seat," after which they should be buckled into a belt-positioning booster seat in the back seat.

The National Highway Traffic Safety Administration states that you should 'keep your child in a forward-facing car seat with a harness and tether until he or she reaches the top height or weight limit allowed by your car seat’s manufacturer. Once your child outgrows the forward-facing car seat with a harness, it’s time to travel in a booster seat, but still in the back seat. your child should stay in a car safety seat with a full harness until the seat is outgrown, usually at about 40 pounds.' The NHTSA also offers an age range of 4 to 7 years as a good time for when kids might be ready to move to a booster seat.

Booster Seat Limits

Of course, your child would also have to meet the car seat's height limits for using the harness straps. That isn't very hard these days, as most convertible seats have fairly high forward facing weight and height limits (65 pounds and 49 inches).

Why do they sell booster seats without harness straps with weight limits below 40 pounds if you should use a harness strap below this weight? Mainly because some taller kids outgrow their car seat even before they reach 40 pounds. So if your child's shoulders are above the top set of strap slots on your car seat, then you can move him to a belt-positioning booster seat, or simply stop using the harness straps if you have a combination seat, and now use the car seat as a belt-positioning booster.

Or because some kids complain about being in a car seat and want to be in a big kid booster.

Car Seats With High Harness Limits

The following car seats have even higher high weight and height limits (80-90 pounds and 52-58 inches), so you can keep your child in them using harness straps 'as long as possible':

  • Britax Frontier
  • Britax Pinnacle
  • Graco Argos 80 Elite
  • Diono Rainier Convertible + Booster Car Seat with Head Wings

The bottom line is that you shouldn't be in a rush to move your preschooler into a booster seat. To be safe, keep your child in a forward-facing car seat with a harness strap as long as you can.

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Article Sources

  • AAP. Car Seats: Product Listing for 2016.
  • NHTSA. How should preschool and school children ride safely?