Diono Sizing Guide

When choosing a child safety product such as a car seat or stroller, it’s essential to select one that fits your child’s size. Fortunately, the engineers at Diono have poured a tremendous amount of energy into making this a non-issue, designing all-in-one car seats and strollers that adjust to fit any child. This brief sizing guide illustrates the extraordinary versatility of Diono’s child travel safety products, which are designed to set your mind at ease with regard to size so that you can focus on other product features. Once you've reviewed this page, head on over to our Diono collection to shop now for strollers and child car seats!

Child Car Seats

Diono’s flagship Radian line of child car seats is rated for children from 5 to 120 pounds (2.2 to 54 kg), so that your newborn can use the same car seat for the next ten years.

Chart from Diono illustrating the adjustability of the Radian 3QXT child vehicle safety seat

The twelve-position adjustable headrest moves up or down to accommodate taller children, and so does the five-position safety harness. The seat can face the rear of the vehicle for your youngest children, or the front of the vehicle for your eldest. For your largest children, remove the safety harness entirely and use the Radian as a booster seat. It's really quite incredible how versatile this steel-core child safety seat is, so your child stays safer for longer and you never have to buy another seat.


Like their car seats, Diono's strollers are adjustable accommodate children from newborns to toddlers up to about 50 pounds (22.7 kg), or about 4 years old. For instance, the Quantum2 stroller comes with removable padded inserts, whereas the Flexa and Excurze strollers achieve the same adjustability by other means such as adjustable safety harness, calf support, and hood height.

Diono Quantum 2 stroller with removable padded inserts

When sizing a Diono stroller, the more important consideration may be the product's weight and your own stamina for pushing that weight. Diono's lightweight Flexa and Two 2 Go strollers are between 15 and 20 pounds. Its mid-weight Excurze strollers are just over 20 pounds. Its heaviest strollers, the Quantum2 line, exceed 30 pounds. The extra features may be well worth the weight for most customers, but weight is an important consideration if you're a lightweight yourself.