A suit is sized by two numbers working together — a chest size and a length code — and getting both right is the difference between a suit that looks tailored off the rack and one that visibly doesn't fit.
How suit sizing works
Suit sizing format is chest size plus a length code. For example, "40R" means a 40-inch chest measurement with a Regular length. The chest size is measured around the fullest part of your chest, under the arms, over a dress shirt. The length code adjusts the jacket's body length and sleeve length for your height, not your chest size.
Length codes
- S (Short): for men roughly 5'4"–5'7"
- R (Regular): for men roughly 5'8"–6'0"
- L (Long): for men roughly 6'1"–6'4"
- XL (Extra Long): for men 6'5" and taller
Chest measurement to jacket size
| Chest (inches) | Jacket Size |
|---|---|
| 34"–35" | 36 |
| 36"–37" | 38 |
| 38"–39" | 40 |
| 40"–41" | 42 |
| 42"–43" | 44 |
| 44"–45" | 46 |
| 46"–47" | 48 |
| 48"–49" | 50 |
Length code by height
| Height | Length Code | Example Size |
|---|---|---|
| 5'4"–5'7" | S (Short) | 40S |
| 5'8"–6'0" | R (Regular) | 40R |
| 6'1"–6'4" | L (Long) | 40L |
| 6'5"+ | XL (Extra Long) | 40XL |
The pants "drop"
Suit pants are almost always sold with a fixed relationship to the jacket size, called the "drop." Most off-the-rack suits use a 6-inch drop, meaning the waist of the included trousers is 6 inches smaller than the jacket's chest number. A 40R jacket therefore ships with a 34-inch waist pant. Some brands offer a 7-inch "athletic" drop for a more built chest-to-waist ratio, or a 5-inch "portly" drop for a fuller midsection. If your waist doesn't match your jacket's drop, buy separates rather than a matched suit.
Looking for a specific brand?
Fit varies far more between brands than between size systems.
Browse 30+ brand size chartsWhat to prioritize when buying
Buy for the shoulders — everything else on a jacket can be tailored, but shoulders cannot. If the shoulder seam sits noticeably beyond your natural shoulder point, or the fabric bunches at the seam, size down or try a different cut, since no tailor can move a shoulder seam without rebuilding the jacket.
- Shoulders: the seam should sit exactly at the edge of your shoulder bone.
- Chest: you should be able to fit a flat hand between your chest and the buttoned jacket, no more.
- Sleeve length: jacket sleeve should end so that about a half-inch of shirt cuff shows.
- Jacket length: should cover your seat and roughly reach the middle of your palm when your arms hang relaxed.
- Trouser break: a slight single break at the shoe is the modern standard; no break (cropped) is more fashion-forward, a full break is dated.
Off-the-rack alterations that are easy vs. hard
Easy and inexpensive: sleeve length, trouser hem, waist taken in, jacket taken in at the sides. Difficult or impossible without rebuilding the garment: shoulder width, jacket lengthened significantly, letting a jacket out more than an inch at the chest.
US to EU suit size conversion
| US Size | EU Size |
|---|---|
| 36 | 46 |
| 38 | 48 |
| 40 | 50 |
| 42 | 52 |
| 44 | 54 |
| 46 | 56 |
If you're unsure between two chest sizes, size down for a modern slim silhouette (since the shoulders and chest can't be let out much) or size up if you plan to layer a sweater underneath. Cross-check against the specific brand's chart, since "40R" from one maker can measure an inch different from another — use the size converter to compare, and see how to measure yourself for exact chest and sleeve measurements before you buy.
Vest and separates sizing
If you're buying a three-piece suit or separate vest, the vest typically follows the jacket's chest size directly rather than the trouser drop. A 40R jacket pairs with a size 40 vest. Some formalwear rental houses size vests using a "small/medium/large" band instead — in that system, a 40 chest usually corresponds to a size 40 or Medium-Large band, so always check the specific retailer's own chart before ordering online.
Fabric weight and seasonal fit
A suit's fabric weight affects how snug the labeled size feels. Lightweight tropical wool (around 7–9 oz) drapes closer to the body and can make a true-to-size jacket feel slightly looser than a heavier flannel or worsted wool (12–14 oz) in the same size, since heavier cloth holds more structure and adds visual bulk. If you're buying a suit to wear with a sweater or vest underneath in colder months, consider sizing up half a size in the chest, or ask your tailor to leave slightly more room in the side seams during alterations.
Buying a suit for a specific occasion
For weddings and formal events where a suit will only be worn a handful of times, renting or buying budget separates in a true-to-chart size is usually sufficient since minor imperfections matter less for one-day wear. For a suit intended for weekly work use, it's worth having even a well-fitting off-the-rack jacket tailored at the waist and sleeves — a $30–$60 alteration typically improves the overall silhouette more than upgrading to a pricier brand at the same rough size.