Quick answer: To measure your chest, stand with your arms by your sides and wrap a tape round the fullest part of your chest, high under the armpits and across the shoulder blades. Keep it level and breathe normally. The result in inches is your UK jacket size, so a 40 in (101.6 cm) chest wears a 40, or EU 50.
Chest size is the starting point for almost every men’s top half: jackets, coats, knitwear and T-shirts. It takes a minute to measure, and once you have it you can read any UK, European or letter-size chart with confidence. This guide covers the technique, the common slip-ups and how the number converts into S, M, L and suit sizes. For other measurements, see our body and clothing measurement guides.
Where is the chest measured on a man?
Round the fullest part of the chest, with the tape close under the armpits and across the shoulder blades. On most men that is roughly level with the nipples at the front, but the tape should be guided by the armpits, not by any one landmark.
The European size standard BS EN 13402-1 describes chest girth as the maximum horizontal girth, measured during normal breathing, passing over the shoulder blades, under the armpits and across the chest. ASOS gives shoppers the same instruction in shorter form: measure round the fullest part, with the tape close under the arms and flat across the back.
What do you need?
- A soft tape measure with inches and centimetres. If the inch fractions trip you up, our guide on reading a tape measure explains them.
- A thin T-shirt, or bare skin. A shirt and jumper together add bulk and inflate the reading.
- A mirror or a helper to check the tape is level across your back.
How do you measure your chest step by step?
- Stand up straight and relaxed, feet together and arms hanging naturally. Do not fold your arms or put your hands on your hips.
- Lift your arms slightly and pass the tape round your back, high under the armpits.
- Lower your arms so they rest on the tape. This stops it slipping and keeps it in the right place under the arms.
- Check the back. In a mirror, or with a helper, make sure the tape crosses the shoulder blades and is level, not sagging towards the waist.
- Breathe out normally and read the tape where it meets the zero end at the front. It should lie flat without digging in.
- Repeat once and note the result in inches and centimetres.
Measuring alone works well if you use a mirror, because your arms hold the tape in place. The one thing that is hard to do on your own is check the back, so take a quick look over your shoulder before you read the number.
What size is my chest in inches and in Europe?
Divide centimetres by 2.54 to get inches; add 10 to a UK jacket size to get the European size. Enter your chest measurement below to see both.
Chest to jacket size calculator
cm chest= in · UK jacket · EUThe calculator rounds to the nearest even size, because most UK jackets are made in 2 in steps. If you land exactly between two sizes, try both, as cut and fabric make a difference. For other conversions, use the cm to inches converter.
What chest size is S, M, L and XL in the UK?
On the ASOS men’s chart, a medium fits a 38 to 40 in (96 to 101 cm) chest and a large fits 40 to 42 in (101 to 106 cm). Letter sizes are not standardised in the UK, so other brands may shift each band by an inch or so either way.
| Letter size | Chest (inches) | Chest (cm) |
|---|---|---|
| XS | 34–36 in | 86–91 cm |
| S | 36–38 in | 91–96 cm |
| M | 38–40 in | 96–101 cm |
| L | 40–42 in | 101–106 cm |
| XL | 42–44 in | 106–111 cm |
| XXL | 44–46 in | 111–116 cm |
| XXXL | 46–48 in | 116–121 cm |
Source: ASOS men’s jumpers and cardigans size guide. Where a measurement sits on the boundary between two bands, such as exactly 40 in, the fit you prefer decides it: the smaller size for a close fit, the larger for layering.
How does chest size relate to suit and jacket sizes?
A UK suit jacket size is your chest measurement in inches, and the European size is that number plus 10. A 42 in chest wears a UK 42, which is a 52 in Italian and German sizing.
| Chest (inches) | Chest (cm) | UK and US jacket | European jacket |
|---|---|---|---|
| 34 in | 86.36 cm | 34 | 44 |
| 36 in | 91.44 cm | 36 | 46 |
| 38 in | 96.52 cm | 38 | 48 |
| 40 in | 101.60 cm | 40 | 50 |
| 42 in | 106.68 cm | 42 | 52 |
| 44 in | 111.76 cm | 44 | 54 |
| 46 in | 116.84 cm | 46 | 56 |
| 48 in | 121.92 cm | 48 | 58 |
The length letter (S, R or L) is chosen separately, mainly by height and arm length. For the full process, including sleeve and trouser measurements, see how to measure for a suit.
Why is the jacket bigger than my chest measurement?
Because size labels describe your body, while the garment itself is cut larger so you can move. That extra room is called ease, and it varies with the fit.
Charles Tyrwhitt’s suit size guide shows this clearly. Its classic-fit size 44 jacket has a garment chest of 47 in, while its slim-fit size 40 has a garment chest of 42.5 in. In other words, the classic cut adds about 3 in to the body size and the slim cut about 2.5 in. When a product page lists a garment measurement, do not compare it directly with your body measurement; compare it with a similar garment you own instead.
To do that, lay a well-fitting jacket or jumper flat, buttoned up, and measure straight across from armpit seam to armpit seam. Double the figure for the garment’s full chest. That is often the quickest way to choose between two sizes online.
Do shirts use chest size?
Formal shirts in the UK are mainly sold by collar size, with fit names such as classic, slim or extra slim covering the chest. Your chest measurement helps choose the fit, but the collar decides the size. See our guides to measuring collar size and shirt size.
Should you measure differently for a coat?
No: use the same body chest measurement, taken over a thin T-shirt. Coats and outdoor jackets are designed to go over other clothes, so the extra room for a shirt or light jumper is already built into the pattern. Measuring over your thickest jumper counts that allowance twice and usually leaves you with a coat that is too big in the shoulders.
The exception is a technical shell or rain jacket that you plan to wear over a bulky fleece or insulated layer. Many outdoor brands publish their own guidance for this, so check the product description. If it says nothing, compare the garment chest with a coat you already own that fits well over the same layers.
Common mistakes to avoid
- Puffing the chest out. A deep breath expands the ribcage and inflates the reading. Breathe normally.
- Letting the tape drop at the back. If it slides down below the shoulder blades, you are measuring a smaller, diagonal loop.
- Measuring over a jumper. Thick layers inflate the result and push you up a size.
- Measuring round the stomach. If your stomach is larger than your chest, measure it separately as your waist and check both on the size chart.
- Comparing body and garment sizes. A jacket with a 44 in garment chest is not a size 44. Read which kind of measurement the chart gives.
Frequently asked questions
How do I measure my chest size for a jacket?
Wrap a tape round the fullest part of your chest, close under the armpits and across the shoulder blades, with your arms down and breathing normally. Your chest in inches is your UK jacket size.
What chest size is a men’s medium in the UK?
On the ASOS men’s chart, a medium fits a 38 to 40 in chest, which is 96 to 101 cm. Other brands may differ slightly.
What is a UK 40 chest in European sizes?
A UK 40 jacket is a European 50. Add 10 to the UK size to get the Italian or German size.
Should I breathe in when measuring my chest?
No. Breathe normally and read the tape at a relaxed breath. Holding a deep breath makes the measurement too large.
Is chest size the same as the jacket’s chest measurement?
No. The size label refers to your body chest. The jacket itself is cut a few inches larger to allow movement.
Sources
- BSI: BS EN 13402-1 Size designation of clothes: definition of chest girth.
- ASOS men’s jumpers and cardigans size guide: letter sizes by chest measurement.
- Charles Tyrwhitt suit size guide: garment chest measurements for classic and slim fits.
- National Physical Laboratory: the inch is exactly 2.54 cm.