Note: This is a general sizing guide. Some items can differ depending on the brand. 
Womens Dresses and Tops
size xs s m l xl
bust 30 32 36 37 40
waist 24 26 28 30 32
hips 34 36 38 40 42

Plus Size Dresses and Tops
size 1x 2x 3x 4x
bust 38 40 42 44
waist 32 34 36 38
hips 42 44 46 48

Womens Bottoms
size xs s m l xl
00 0 1 3 5 7 9 11 13
waist 26 27 28 29 30 31 32 33 34
hips 32 33 34 35 36 37 38 39 40

Plus Size Bottoms
size 1x 2x 3x 4x
14 16 18 20 22 24 26 28
waist 35 36 37 38 40 41 43 44
hips 40 41 42 44 45 47 48 50
adult size chart illustration
a. How to measure your Bust:
With your arms relaxed at your sides, measure the fullest part of your chest. 
b. How to measure your Waist:
Measure around the narrowest part of your natural waist, generally around the belly button. To ensure comfortable fit, do not measure too tightly. 
c. How to measure your Hips:
With your feet approximately 6 inches apart, measure around the fullest part of the hips. this area corresponds to the top of your legs.