Dress shirts and many jackets are sold with a sleeve number, such as 34 or 35, and it is one of the least understood sizes. It is not your arm length: it is measured from the back of the neck, across the shoulders and down the arm, so it is far longer. This calculator takes that measurement and your preferred cuff allowance and gives the sleeve length to buy, together with the matching size on a standard shirt chart.
How to use the sleeve length calculator
- Stand relaxed with your arm slightly bent at the elbow, ideally with a helper holding the tape.
- Start the tape at the top of the centre back, just below the collar line, and run it over the shoulder where the shoulder bone ends, then down the arm to the wrist bone.
- Enter the measurement and the allowance you want past the wrist bone (half an inch by default).
- Read the sleeve length. It is rounded up to the next half inch.
Sleeve length formula
cm = inches × 2.54
allowance: ½ inch past the wrist bone (Turnbull & Asser)
The measuring method is the same in the guides from Marks & Spencer, Hawes & Curtis and Charles Tyrwhitt, and the half-inch allowance is from Turnbull & Asser (retrieved 2026-10-15). Sleeve sizes on the M&S formal shirt chart run from 34 inches for a small to 39 for a 5XL.
| M&S size | Neck (cm) | Neck (in) | Chest (in) | Sleeve (in) |
|---|---|---|---|---|
| S | 36–37 | 14–14.5 | 34–36 | 34–34.5 |
| M | 38–40 | 15–15.5 | 38–40 | 35–35.5 |
| L | 41–42 | 16–16.5 | 42–44 | 36–36.5 |
| XL | 43 | 17 | 46 | 36.5 |
| 2XL | 44–46 | 17.5–18 | 48–50 | 37–37.5 |
| 3XL | 47–48 | 18.5–19 | 52–54 | 37.5–38 |
| 4XL | 49–50 | 19.5–20 | 56–58 | 38–38.5 |
| 5XL | 52–53 | 20.5–21 | 60–62 | 38.5–39 |
Worked example
Centre back to wrist bone 34.5 in, with the usual half inch allowance.
- 34.5 + 0.5 = 35.0 in, already on a half inch → sleeve 35.0 in (88.9 cm).
- On the M&S chart that is a M (sleeve 35–35.5 in).
Avoiding common mistakes
- Bent arm: measuring with a straight arm gives a number that is a little too short, so keep the arm slightly bent.
- Shoulder point: stop at the end of the shoulder bone, not at the neck line.
- Different brands: some makers measure to the centre of the palm; use their own guide.
- Tailoring: sleeves are easy to shorten, hard to lengthen.
The Collar / Neck Size Calculator covers the other half of a dress shirt size. See also the Shirt Size Calculator and Suit Size Calculator. This page is general guidance.
Sources
Every figure above comes from these pages, read directly on the dates shown. Brand names are used only to identify published charts.
- Marks & Spencer — formal shirts size guide (sleeve lengths, measuring advice) — checked 2026-10-15
- Hawes & Curtis — how to measure (sleeve from the top of the centre back) — checked 2026-10-15
- Charles Tyrwhitt — how to measure for a shirt — checked 2026-10-15
- Turnbull & Asser — shirt size guide (half an inch past the wrist bone) — checked 2026-10-15
- Proper Cloth — dress shirt body measurements (sleeve to the palm) — checked 2026-10-15
Frequently asked questions
How do I measure sleeve length?
With your arm slightly bent, start the tape at the centre back of the neck, run it over the shoulder where the shoulder bone ends and down the arm to the wrist bone. Marks & Spencer, Hawes & Curtis and Charles Tyrwhitt all describe this method.
How far past the wrist should a sleeve go?
Turnbull & Asser suggest finishing half an inch (1.3 cm) past the prominent bone of the wrist. Proper Cloth, which makes custom shirts, measures to the centre of the meaty part of the palm instead, so the endpoint depends on the maker.
Why is my shirt sleeve number so large?
A shirt sleeve is measured from the centre back, over the shoulder, so it is much longer than your arm: 34 to 38 inches rather than 24. The sleeve number includes the back and shoulder.
Is sleeve length the same as arm length?
No. Arm length runs from the shoulder to the wrist; shirt sleeve length runs from the centre back of the neck. Use the same method as the shop.
What if I am between lengths?
Choose the longer one, since the cuff can be rolled or a tailor can shorten it. Pair the sleeve with the collar from the Collar / Neck Size Calculator.