How do you measure your arm span?

Answer 1

Have someone use a tape measure to do it as you hold your arms out as far as you can, measure finger tip to finger tip.

Answer 2

I did this myself the other day as I was ordering a jacket online.

Anyway, I got a tape measure and put the 0 at my left longest fingertip, then closed my thumb against my palm to hold the tape measure where it was.

Then just extended my arms while letting the tape measure run through my right hand until my arms were fully straight along with the tape measure (not bend back against my chest).

I then gripped the loose end with my right thumb against my palm as I had done with my left hand. This held it in place so i could just bring my hand back, extend the tape measure the rest of the way and simply read off the number at my right longest fingertip.

It was 197cm, marvellous. Only took about 5 seconds, do it now!

Answer 3

Get a tape measure grip in one hand the unit itself
in the other hand grab the tape of the tape measure and
then spread your arms as far apart as possible then make sure you don't drop the tape measure or you'll have to do it all again.

Answer 4

Hold your arm straight out in front of you and have someone measure from your wrist to your shoulder (it might actually be the middle of the chest now that I think of it)