The below size guide will help;
Waist: Place one end of the tape measure at your natural waist, you want to find the narrowest part of your waist. Don’t go up too far or too low to get an accurate measurement. Don’t hold the tape too tight or your clothing will be hard to move in.
Hips: Stand with your legs together and measure the fullest part of your hips. Be sure to go over your
bottom as well. It might be challenging to keep the tape consistently level when you do it alone.
Inside leg: The inseam is the distance of your inside leg measuring from the top of your inner thigh to your ankle. It is easiest to measure the inseam based on a well-fitting pair of pants. Measure from the crotch tothe cuff on the inside seam of the leg. The number of inches, to the nearest ½”, is the inseam length. It’s best to measure your inseam with a pair of shoes on so that you can ensure the hem hits at the right point on your shoe.