Suit Size Calculator your chest is your size
Enter your chest, waist and height. You get the jacket number, the length letter, the EU equivalent and the trouser waist that comes with them.
One Measurement Decides It
The US jacket number IS your chest in inches. Everything else follows from it.
Brands Vary
Sizing conventions are consistent; individual cuts are not. Always try before buying.
How is suit size measured?
At a Glance
A suit size like 40R is two things: a number that is your chest measurement in inches, and a letter for jacket length taken from your height. The trousers that come with it are not measured from your waist at all — they are the jacket size minus a fixed "drop".
Three conventions, applied in order.
US size = chest in inches, rounded to the nearest even number · EU size = US size + 10The length letter comes from height. Short below roughly 172 cm (5 ft 8), Regular up to about 185 cm (6 ft 1), and Long above that. The letter changes the jacket body length and the sleeve, not the chest.
The trouser waist comes from the drop, not from your measured waist:
trouser waist = jacket size − drop (6 in classic, 7 in athletic, 8 in slim)That last convention is why suits so often need altering. If your real waist is more than about two inches away from the drop, the trousers will be noticeably loose or tight — the calculator flags this rather than pretending the number fits.
The defaults are a 102 cm chest, 89 cm waist and 180 cm height in a classic cut.
Convert the chest
102 ÷ 2.54 = 40.16 inches, which rounds to a 40 jacket.
Add the length letter
180 cm falls in the Regular band, so the size is 40R. The EU number is 40 + 10 = 50.
Apply the drop
A classic cut drops six inches: 40 − 6 = 34-inch trousers. The measured 89 cm waist is 35 inches, close enough that no alteration is flagged.
Switch to a slim cut
The slim drop is eight inches, so the same jacket now comes with 32-inch trousers — three inches under the real waist, and the calculator says tailoring is likely.
Check a shorter frame
A 97 cm chest at 168 cm gives 38S, EU 48, with 32-inch trousers.
The conventions here are consistent. Individual garments are not.
Brands cut differently within the same nominal size. Two 40R jackets from different makers can differ by an inch across the chest and considerably more in the shoulder. Treat the number as the size to try first, not the size to order blind.
The shoulder decides the fit, and it is not in the calculation. A jacket can be let out at the waist and shortened at the sleeve, but the shoulder seam is the one alteration tailors avoid. If the shoulder is wrong, the size is wrong.
The drop is a convention, not a measurement of you. If your waist sits far from it, buying the jacket and having the trousers altered — or buying them separately where a maker allows it — is the normal answer.
Measure over a shirt, not over a jumper, and keep the tape level. A centimetre of error moves you a whole jacket size at the rounding boundary.
European makers sometimes label in centimetres of half-chest, so a 50 can appear as 100. Check what a label means before assuming an offset.
For measurement conversions on their own, use the Height Converter.