How to measure a coin (mm) for capsule fit

Tools you need

• Digital calipers (0.01 mm resolution is ideal).
• Soft, clean work surface and nitrile or cotton gloves.
• Microfiber cloth and a dust blower.

Step-by-step

1. Zero calipers and check with a known object.
2. Measure diameter at two or three angles; note the largest reading.
3. Check rim height visually—proofs or high rims may prefer a looser/ring fit.
4. Consider thickness if your capsule spec lists max thickness.
5. Pick the fit: tight display vs 1 mm looser or ring option.

Quick rules of thumb

• Display-tight look? Choose the exact mm capsule (direct-fit).
• Safer closure or proofs? Choose +1 mm or a ring capsule with the inner size matching your coin.
• Uncertain? Find the coin page (e.g., 2 Euro coin).