Take a piece of paper and a pen or pencil
Stand with your heels against the wall
Stand upright, placing your weight on both feet
Get someone else to draw a line be the tip of your toe
Measure the length from the wall to the line
Add 3-5 mm to the measured length (important for toe space)
Compare the foot length with size chart
Very light, flexible boots. Will be great for wilderness kayaking. My second pair for this. The only confusing thing in the ordering is that the size as marked on the boots has changed. Make sure you know that a size 7 mens is a 39 European