To know what your size is, follow the following steps:
Surround the narrowest part of your waist with a tape measure.
Stand with your feet together and surround your hips with a tape measure in the highest volume part ..
This is easier to explain than to do. Because, what if you’re right between two sizes?
You choose. Do you fit the fitted clothes? Choose the smallest size. Do you like baggy clothes? Choose the largest size.
Size of pants: If you have different size of waist than hips, choose your size of pants according to your hips.