How big does a blanket need to be?

[netto]

I am knitting a baby blanket to be used in a silver cross pram. It's with pom pom wool so won't need to be folded.
Can anyone give me an idea how long it should be please?
Thank you

Ask the parents to measure the pram?

It's a gift so I'm trying to avoid asking them.

Have a google of silver cross pram blankets or look on John Lewis for inspiration. but I'd say at least 1m square or more to allow for folding over.

Does this help? I wouldn't say very big if it doesn't need to be folded!

I'd do a square metre regardless.

Thank you so much everyone.
@FTM2022SSthat's really handy.