MEASUREMENT GUIDE · ARM LENGTH

How to Measure Arm Length
— Upper & Lower Arm with Hand Spans

May 4, 2026 · Updated 2026.05.30 · FITME Measurement Guide

Measuring arm length in two segments — upper arm (shoulder to elbow) and lower arm (elbow to wrist) — is more accurate than measuring the full arm at once. It also gives you the proportion data needed for sleeve length and arm ratio analysis.

Arm length measurement guide — upper arm and lower arm with hand spans

Total arm length sets jacket and shirt sleeves — upper plus lower segments. Jacket sleeve ≈ total arm; shirt sleeve ≈ jacket + 1–1.5 cm.

Step A — Upper Arm (Shoulder to Elbow)

STEP A

Arm relaxed at side — shoulder seam to elbow bone

Let your arm hang naturally at your side. Place your span's thumb at the shoulder seam point (acromion) and count how many spans fit to the outer elbow bone (lateral epicondyle). Measure along the outer arm.

Upper arm spans × span cm = Upper Arm Length

e.g. 2 spans × 18cm = 36cm (avg male upper arm ~32–36cm)

Step B — Lower Arm (Elbow to Wrist)

STEP B

Arm extended — elbow bone to wrist bone

Extend your arm forward. Place your span's thumb at the outer elbow bone and count spans to the outer wrist bone (ulnar styloid). Measure along the outer (pinky-side) forearm.

Lower arm spans × span cm = Lower Arm Length

e.g. 1.5 spans × 18cm = 27cm (avg male lower arm ~25–28cm)

💡 Total arm length = upper + lower. Shoulder tip to wrist is typically ~3–3.5 spans. This is the primary number for determining sleeve length.

Why Arm Length Matters for Fit

Sleeve length is one of the most visible fit problems. Even a perfectly fitted shoulder and chest is ruined by sleeves that are too long or short. Shirt sleeves should extend ~1–1.5cm beyond the jacket sleeve; jacket sleeves should just reveal the wrist bone.

Sleeve length rarely shows on the size tag. Torso fit, sleeves wrong—“failed again” and return. Trend chasing looked good in photos; fit kept missing at the wrist. Rough arm numbers gave me a “this sleeve should work” sense.

The ratio between your upper and lower arm is also a key data point in body proportion analysis — FITME uses it to generate your arm proportion score and sleeve style recommendations.

💡 Body proportion fact: forearm length ≈ foot length. Compare yours — they're usually within 1cm of each other.

Sleeve Length and Arm Length — The Exact Calculation

Shirt and jacket sleeve length (measured from the shoulder seam to the wrist bone) is essentially your total arm length. When buying off-the-rack, jacket sleeves should match your total arm length or be 0.5cm shorter; shirt sleeves should extend 1–1.5cm beyond the jacket cuff. Brand size charts for dress shirts typically follow: S (58–60cm), M (61–63cm), L (64–66cm) — but this varies 1–4cm between brands. If your arm length falls ±3cm outside average, you'll encounter sleeve fit issues across garment categories. The fix — sleeve length alteration (hemming the cuff) — is the cheapest and simplest alteration in tailoring, typically costing very little. Always buy to fit the shoulder and chest; budget for sleeve alterations as needed.

Upper Arm : Lower Arm Golden Ratio

Proportion research suggests the most visually balanced arm ratio is upper arm : lower arm = 1 : 0.8 — meaning the upper arm is about 20% longer than the forearm. For example, upper arm 34cm and lower arm 27cm gives a ratio of 1 : 0.79, close to ideal. When the lower arm is longer than the upper (ratio reversal): sleeves frequently expose the wrist, and the arm looks proportionally long when hanging. When the upper arm is much longer: the sleeve feels short in the upper section and the armhole can feel constraining. FITME's proportion analysis uses this ratio to generate your arm proportion score and to recommend sleeve style (standard length, roll-up, or oversized sleeve).

Styling Strategies for Arm Length

Long arms (top 20% for total arm length): Sleeve roll-ups or fold-ups become a natural style opportunity rather than a problem — the cuff becomes a visual detail. ¾-length sleeves on off-the-rack items will often hit the right spot on long-armed wearers. For full-length sleeves that fall short, a sleeve extension alteration can solve it permanently.

Short arms (bottom 20% for total arm length): Full-length sleeves frequently cover the hand. A cuff hem alteration is the straightforward solution. For casual wear, intentionally wearing long sleeves with the cuffs folded (hand-warmer style) converts a fit issue into a deliberate styling choice. When purchasing long-sleeved items, budget for sleeve alterations from the start — it's the most cost-effective approach.

💡 Related: Leg Length Ratio — How to Look 5cm Taller — the same visual proportion principles applied to leg length and outfit construction.