1. Find your wearing line
A hat may sit higher, lower or with a slight tilt. Measure along the line where the inner band will actually sit rather than following an abstract standard position.
That line is often slightly above the eyebrows and upper ear line, but your real wearing position matters more than a universal diagram.
2. Measure without pulling tight
The tape should touch the head without digging into it. Keep it level and make sure the back does not drift noticeably above or below the intended line.
Repeat the measurement several times. If the results differ, check the tape position and keep the readings for the fit discussion.
3. Record the exact result
Record the exact value in centimetres without rounding it to a hat size. The final size depends on the construction of the model and is confirmed before ordering.
For reference, inches equal centimetres divided by 2.54, but keeping the original centimetre measurement reduces conversion errors.
Common mistakes
- pulling the tape too tight;
- measuring on a diagonal without noticing it;
- rounding down to a convenient-looking size;
- using the label from an old hat instead of a fresh head measurement;
- ignoring a higher or lower preferred wearing line.
If you are unsure
Keep the exact measurement and, if useful, a photo showing your normal wearing line. For a made-to-order hat it is better to resolve uncertainty before work begins than to compensate for an inaccurate measurement later.