Even if you think you know your size, it can be difficult to buy a pair of pants without taking an armful of possibilities labeled with a bewildering array of numbers to a changing room. But if you keep a sizing strip in your wallet, you'll always be prepared when the line is too long or for marathon thrifting sessions.
First gather several of your favorite pairs of pants. They should all have the same rise (mid, low or high).
Cut a strip of paper about ｽ an inch wide and long enough to stretch across the width of your pants. Piece extra length with tape as needed. Mark one side as the starting side.
Lay your pants out flat. Lay the strip across the pants to take the key measurements. Make a pencil mark for each pair of pants, and then draw a pen mark or note a range that summarizes the measurements.
1. (red) Across the waist band 2. (yellow) From the top of the center back waistband down to the crotch seam 3. (green) From the crotch seam directly across to the side seam of one leg 4. (blue) From the center of the front button down to the crotch seam
The 4th (blue) measurement tells you your rise, and should be within a couple of inches on all your model pants. If you wear more then one rise, you may need to make a different strip for each one, as the waist measurement may be substantially different between rises.
Cut a second strip of paper and transfer your marks. Save one of the strips as a backup and put the other in your wallet. If a pair of pants (or shorts) in the store matches the measurements on your strip, chances are you will like the fit.