US to UK hat size
Convert a US hat size to UK in one step. Enter your US size and read the UK equivalent, or use the full chart below.
US to UK hat size chart
| US size | UK size | Head (cm) |
|---|---|---|
| 6 5/8 | 6 1/2 | 53 |
| 6 3/4 | 6 5/8 | 54 |
| 6 7/8 | 6 3/4 | 55 |
| 7 | 6 7/8 | 56 |
| 7 1/8 | 7 | 57 |
| 7 1/4 | 7 1/8 | 58 |
| 7 3/8 | 7 1/4 | 59 |
| 7 1/2 | 7 3/8 | 60 |
| 7 5/8 | 7 1/2 | 61 |
| 7 3/4 | 7 5/8 | 62 |
| 7 7/8 | 7 3/4 | 63 |
| 8 | 7 7/8 | 64 |
US and UK hat sizes are both based on head measurements, so once you know your head circumference you can read either label from the chart. The small differences between the two systems come from how each rounds the head diameter to a printable number, not from any real difference in fit.
If your head circumference sits between two rows, round up, particularly for a structured or fitted hat. To measure accurately, see how to measure hat size.
Common questions
How do I convert a US hat size to UK?
Find your US size in the chart and read across to the UK column, or use the converter above. Both map to the same head circumference, so the conversion is exact.
Is a US hat size the same as UK?
The numbers differ slightly because US and UK round the head diameter differently, but they describe the same head circumference. The chart lines them up precisely.
What if I am between two hat sizes?
Round up for comfort, especially for fitted caps that do not stretch much.
Last reviewed and updated on July 2, 2026. Conversion tables are checked against published international sizing standards.