Choose chest size (numbers) or letter size (XS–XXL) first. Then pick your size in any system — EU suit sizing is one of the more reliable conversions in this whole site: it's a flat +10 over the US/UK number, all the way up the range.
Wrap a tape measure around the fullest part of your chest — under the arms, across the shoulder blades — keeping it level and snug but not tight. Match the result to the nearest size on the chart below; if you're between two, most tailors suggest sizing up for a jacket, since it's easier to take one in than let it out.
Suit and jacket sizing is unusually well-behaved: US and UK use the identical chest-inch number, and the EU size is simply that number plus 10, all the way from a US 34 (EU 44) to a US 48 (EU 58). It tracks the chest measurement the jacket is cut for, so this +10 offset holds steady across most mainstream brands — no rounding, no half-sizes to worry about.
Where it gets less predictable is cut and drop — the difference between chest and waist measurement that defines "regular," "slim," and "long" fits. The size *number* converts reliably; how a specific jacket actually sits on your body doesn't, so treat the size chart as the first step and a fitting (or the brand's own shoulder/waist measurements) as the second.
| US / UK | EU | Chest measurement |
|---|---|---|
| 34 | 44 | 86 cm / 34" |
| 36 | 46 | 91 cm / 36" |
| 38 | 48 | 97 cm / 38" |
| 40 | 50 | 102 cm / 40" |
| 42 | 52 | 107 cm / 42" |
| 44 | 54 | 112 cm / 44" |
| 46 | 56 | 117 cm / 46" |
| 48 | 58 | 122 cm / 48" |
| Letter | US chest | EU chest |
|---|---|---|
| XS | 34 | 44 |
| S | 36 | 46 |
| M | 38-40 | 48-50 |
| L | 42 | 52 |
| XL | 44-46 | 54-56 |
| XXL | 48 | 58 |
Letter sizes don't capture cut (slim/regular/long) — the numeric chest size above is the more precise figure.
A US 40 suit is an EU 50 — EU suit sizes are consistently 10 higher than the US/UK number across this chart's full range.
Wrap a tape measure around the fullest part of your chest, under your arms and across your shoulder blades, keeping the tape level and snug but not tight. Match that measurement to the closest size on the chart.
The size number converts the same way regardless of cut, but "slim," "regular," and "long" fits vary enough between brands that you should still check shoulder and waist measurements, or try the jacket on.