Sizing a sandal you cannot try on

Almost every sandal that gets sent back is sent back over length. It is a solvable problem, and it takes ten minutes with a sheet of paper.

Measure in the evening

Stand on the paper with your weight on the foot, heel against a wall, and mark the longest toe. Do it at the end of the day. A foot measured at eight in the morning is not the foot that will be in the sandal at six in the evening, and the difference runs to several millimetres.

Measure both feet. Buy for the longer one; nobody has a matched pair.

Between two sizes

• Thong or flip flop. Take the larger. A thong that is short pushes the heel over the back edge, and that is where a sandal starts to hurt.
• Wide slide. Take the larger too, unless the strap is elastic. A slide is forgiving at the toe and unforgiving across the instep.
• Closed slipper. Take the smaller. Plush lining packs down over a few weeks and a roomy slipper becomes a loose one.

One model, one last

Colorways of the same listing are the same shoe in different materials on the same mould. If a size worked in one shade it works in the rest, which makes the second pair a far safer purchase than the first.

Read the chart, not the number

The size chart on a listing is measured in centimetres of insole. That number is the one to compare against your paper mark. Two brands calling something an 8 can be a full centimetre apart; two charts cannot.