What is the average blanket size for a quarter horse?

Want to be prepared for my first horse, I know every animal is different... Just want an average so I know what to look at.

it depends on how tall the horse is but for 17 hands i think its about 2 and a half yards long and 1 and half wide. you might have to check on line though.

Depends on the type of Quarterhorse. Foundation Quarterhorses tend to be fairly small. Mine takes a 72" blanket. Appendix Quarterhorses would be larger, probably needing at least a 76". We have six horses and every one takes a different size blanket. Don't get a blanket until you have measured the length of the horse. Measure from the middle of its chest around the side to the middle of its behind.