A sneaker tag often carries three or four numbers — UK, US, EU, sometimes JP — and sellers quote whichever one they read first. That is where most of the trouble starts.
Why the stated size is not enough
Regions differ. The same shoe is a different number in each system, and a seller saying "it's a nine" may be reading any of them.
Makers differ. Two shoes marked the same size from different makers can be a full size apart in practice.
Models differ within a maker. A running silhouette and a skate silhouette rarely fit the same.
The measurement that settles it
Insole length, in centimetres — take the insole out if it lifts, or measure heel to toe inside the shoe.
Then measure the insole of a pair you already own and like. Comparing one number to another number is the whole method, and it takes two minutes once.
What to ask the seller
- "Can you show the size tag inside, all of it?"
- "Can you measure the insole heel to toe?"
- "Which region is that number?"
A seller who answers the first by holding the tag still has probably answered the other two already. Questions to ask.
Width
Rarely marked and rarely mentioned. If width matters to you, ask for the widest point measured across the sole — it is not a standard measure, but it is comparable to your own pair.
What protection covers
A size materially different from the one described, or a different pair than shown: seven days from delivery.
A pair that fits differently than you hoped, when the tag and the measurement were accurate, is not. That is why you ask first.
Questions people ask
Should I size up in a second-hand pair?
Worn shoes have already stretched a little. Measure rather than guess.
Is the box size reliable?
It is the size printed for that box. Check the shoe itself too.
Can a half size be felt?
In most silhouettes, yes.