Sit with your foot firmly on the floor, and your leg bent slightly forward so that your shin is slightly in front of your ankle and your knee is even with your toes. Trace the outline of your foot and remember to measure your foot without shoes, but with socks similar to the ones you'll be wearing with the Boots that you are buying. Hold the pencil or pen upright and perpendicular to the paper. Do not hold it at an angle. Make sure the pencil is resting snugly against your foot as you draw around it.

You may actually find it helpful to have someone else trace your foot, but as you can see in this image, it can be done alone.

Use your pencil to draw straight lines touching the outermost points at the top & bottom of the outline.

Which means from the two furthest points.

The Longest toe to the outside edge of the heel.

Use your ruler or measuring tape to measure the length from the bottom line to the top line that you drew in step three. Be sure to hold the measuring tape straight, and find the closest mark that you can.

Round this number to the next closest whole or half number.

If the measurement equals 233mm then your rounded measurement would be 235mm.

Write this number down.

Repeat these steps for your other foot, and use the larger of the two measurements.