Both are convertible car seats — here are their published manufacturer specs side by side.
This compares published manufacturer specs — not safety or fit advice. The seat's manual, your vehicle's manual, NHTSA's tools and a certified CPST are the fit-and-safety authority; always check them before installing.
As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Weight ranges are the manufacturer's published limits across all modes.
How they differ
both list the same documented features for the convertible stage — the choice comes down to brand, price and your vehicle's fit (check both manuals)
Published limits
Mode
Britax Allegiance
Maxi-Cosi Pria Max
Rear-facing
5–40 lb
4–40 lb · 19–40 in
Forward-facing harness
20–65 lb
22–65 lb · 29–49 in
Booster (with back)
—
40–100 lb · 43–52 in
Useful life
7 yrs from manufacture
10 yrs from manufacture
Britax Allegiance: Harnessed seat only (no booster mode). Rear-facing 5–40 lb, forward-facing 20–65 lb; the manual's overall height limit is 49″ or less. Discontinue use once the seat is older than seven years (see the Manufactured Date Label).
Maxi-Cosi Pria Max: 3-in-1 all-in-one (rear-facing → forward-facing harness → high-back belt-positioning booster; no backless mode found in manual — the site currently lists this model's stage as "convertible" only, but the manual confirms a booster mode too). Forward-facing requires at least 1 year old.
That is the record of the brand — not a verdict on these models. A recall names specific models and manufacture-date ranges, and a seat missing from the record is not "recall-free": check nhtsa.gov/recalls with the model and date of manufacture on your seat's label. Source: NHTSA, retrieved 2026-09-05.
Need it before the due date or a trip? Amazon Prime includes fast delivery on eligible items, and eligible new members may be offered a free trial. Delivery speed and return terms vary by item, so check the listing in case a seat may not fit your car. See if you can try Prime free →
Affiliate link — we may earn a commission on qualifying sign-ups, at no extra cost to you. Current terms are on Amazon's page.
As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Affiliate links never affect our specs or which seats we compare.
FAQ
What's the difference between the Britax Allegiance and the Maxi-Cosi Pria Max? The Britax Allegiance is FAA-approved for aircraft; the Maxi-Cosi Pria Max is FAA-approved for aircraft. Both are convertible car seats.
Which is right for my car and child, the Britax Allegiance or the Maxi-Cosi Pria Max? That depends on your specific vehicle and child — this page compares published manufacturer specs only, not fit or safety. Check the seat manual, your vehicle manual, NHTSA's car-seat finder and ideally a certified CPST before deciding.
Citing these specs? Go ahead — published manufacturer data, last verified 2026-06-11. Copy a ready-made reference: