for climbing packs: White light/white heat, New Day Rising, alpine machine 40 & 50 with the alpine belt.
measure your circumference where you want the bottom edge of your pack to sit on your back. may or may not be over your hips.
from this line measure straight up to the center of your shoulder, but be careful not to wrap the tape over your shoulder. this should be several inches to the side of your spine. you can use a small level or ruler to measure to.
Do you have straight or sloping shoulders?
please send a photo of you wearing your pack, ideally just in a T-shirt,from the side, arms down, stand straight. then, send a photo of the back of your pack with a tape measure running bottom to top. this is for my reference and can compare it to your body measurements vs pack measurements.
fitting big packs ,anything over 50L.
the same as above plus:
i need you to measure your circumference where you can feel your hip bones stick out towards the front of your pelvis. Then I need a circumference measurement take exactly 4",10 cm, above the hip measurement.
I use these to custom fit the bigger conical waist belts.