Building & DIY

Rivet Size Calculator (Diameter, Length & Hole)

Enter your material thickness and it suggests a rivet diameter, length, and drill hole. It uses the 3-times-thickness rule for normal stock and the Unwin formula for material over 8 mm.

How to use
  1. Enter the combined thickness of the parts you're joining.
  2. Pick the output you want in metric mm or US 1/32-inch sizes.
Estimates only, allow for waste and confirm against local building codes and supplier specs.
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Common questions

What size rivet do I need for a given thickness?

A common rule sets the rivet diameter at about three times the plate thickness for thin stock. For material thicker than 8 mm, the Unwin formula d = 6.05√t gives a better diameter.

How much bigger should the hole be than the rivet?

Just enough for an easy fit, typically a fraction of a millimeter oversize. The calculator gives the nearest standard hole size for your rivet.

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