First thing that you need to know is that you have to measure you legs in the morning!
What to use instead of measuring tape?
A. Find a yarn/rope or a measuring tape.
B. Wrap around your leg to get the circumference.
C. If using a yarn/rope just lay it against the ruler. Advise to the table on the product page of the item you are willing to buy.
Step 1. Ankle. You should always start with measuring ankle.
Measure around your ankle (this measurement is called the circumference). Place the measuring tape at the narrowest part of the ankle, above the ankle bone.
Step 2. Calf
Find the widest part of your calf. Measure the circumference of your calf.
Step 3. Thigh
Find the widest part of your thigh. Measure the circumference of your thigh.
After you write down your metrics, please advice to the size chart displayed on the product page.