Find the Right Watch Size for Your Wrist
Free watch size calculator that turns your wrist circumference into a proportional case diameter, lug-to-lug, thickness and strap width. The calculation uses industry "rule of thumb" proportions (case ≈ 22 + wrist ÷ 4.7 mm) so the watch looks balanced on your wrist instead of too small or oversized. Standard and "slim" presets shift the result by ±2 mm to match personal preference.
How to pick your watch size
Wrap a soft tape around the wrist just past the bone, snug but not tight. Use paper + ruler if needed.
Type or drag the slider to your wrist size in mm or inches.
Slim shifts the target 2 mm smaller for a more elegant dress-watch look.
Case range (e.g. 40–44 mm), lug-to-lug, thickness and strap width.
The SVG shows the case on your wrist — adjust if it looks too dominating or lost.
Match wrist circumference to a proportional case diameter, lug-to-lug and strap width with a live wrist-size preview.
Features
Frequently asked questions
How does the formula work?
The tool uses the widely-repeated proportional rule case_diameter_mm ≈ 22 + wrist_circumference_mm ÷ 4.7. That produces a center value around which ±2 mm marks a well-fitting range. The "Slim" preset shifts the center down by 2 mm.
What wrist size fits a 40 mm watch?
Around 160–180 mm (roughly 6.3–7.1 inches) is the sweet spot for a 40 mm case — the modern mid-size standard for men and larger women. Smaller wrists 150–165 mm usually look best with 36–38 mm, and 185+ mm wrists can handle 42–44 mm.
Is lug-to-lug more important than diameter?
For wearability — yes. A watch with long lugs can look oversized on a narrow wrist even if the case is small. Lug-to-lug should not exceed the flat top of your wrist (usually wrist circumference ÷ 2.5 ≈ 70 mm for a 175 mm wrist).
What is a comfortable strap width?
The classic rule is strap width = case diameter ÷ 2, so a 40 mm case pairs with a 20 mm strap. Straps are typically made in 2 mm increments (18, 20, 22 mm).
Does wrist shape matter?
Yes — a flat, wide wrist can carry a larger case at the same circumference. The tool optimises for the average oval wrist; for very flat wrists you can safely go 1–2 mm larger, and for round/bony wrists 1–2 mm smaller.
How accurate is the measurement if I use a phone charger cable?
Any flexible string or strip works — mark where it overlaps and measure the strip with a ruler. Avoid stiff tape that won't conform to the wrist curve. Expect ±2 mm error, well within the recommended range.
We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.
