Sizing a Skee-Tex thermal boot

Start with the sock

Measure wearing the sock you will actually fish in. A heavyweight boot sock changes the fit by a full size, so measuring in a thin cotton sock and then fishing in a thick wool one is the most common reason a boot comes back.

The moulded size is not the fitted size

The size moulded into the sole is the size of the mould, not the size of the finished boot with its liner in. The sizes we list are what the boots actually fit. If those two numbers disagree, ours is the one to go by.

Measure the foot, not the shoe

Stand on a piece of paper with your weight on the foot. Mark the back of the heel and the end of the longest toe — which is not always the big toe. Measure between the marks in centimetres. Do both feet; most people have one longer than the other, and you size to the longer one.

If you are between sizes, go up

This is the opposite of the advice for a ski boot, and for a good reason. The liner works by holding a layer of still air around the foot and reflecting your own heat back. Squeeze it and you compress that air out, and a tight thermal boot is a cold thermal boot.

Room to move your toes is not slack — it is the insulation doing its job.

Signs you have gone too big

• Your heel lifts noticeably when you walk
• The boot twists on your foot on uneven ground
• You need two pairs of socks to take up the space

One size up is right. Two is not.

Still unsure

Ring the shop or come in. We have been fitting these since 1950 and we would rather spend five minutes on the phone than have you send a pair back.