Rivet Size Calculator

The common rule is to make the rivet diameter about three times the thickness of the thickest sheet being joined. Two-and-a-half times is the minimum, and four times is used for heavier or more highly loaded joints.

Then round that target to the nearest standard rivet size — 3/32, 1/8, 5/32, 3/16 or 1/4 inch. A rivet much smaller than the rule will be weak; one much larger needs excessive edge distance and can distort thin sheet.

For example, a 0.040-inch sheet at the 3-times rule gives 0.12 inch, which rounds to a 1/8-inch rivet. This calculator applies the rule you choose and snaps the result to the nearest standard size.

Rivet length is the grip — the combined thickness of all the sheets the rivet passes through — plus an allowance to form the shop head. For a solid rivet a common allowance is 1.5 times the rivet diameter.

So the length is the total grip plus 1.5 times the diameter. Too short and there is not enough material to form a sound head; too long and the head is oversized or the shank buckles.

For example, a 0.08-inch grip with a 1/8-inch rivet needs about 0.08 plus 1.5 times 0.125, which is roughly 0.27 inch. This calculator works out the length from your grip and the chosen rivet. Blind rivets instead use the manufacturer’s grip range.

Each standard rivet has a matching drill size that gives the right hole clearance. A 3/32-inch rivet uses a #40 drill (0.0980 inch), a 1/8-inch rivet a #30 (0.1285 inch), a 5/32-inch rivet a #21 (0.1590 inch), a 3/16-inch rivet a #11 (0.1910 inch), and a 1/4-inch rivet an F drill (0.2570 inch).

The hole is slightly larger than the rivet shank so the rivet slips in but still fills the hole when driven. Drilling undersize makes the rivet hard to insert; oversize leaves a loose, weak joint.

These drill sizes suit solid rivets. This calculator shows the matching drill and hole size for the rivet it recommends; blind and structural rivets use the maker’s specified hole.

Edge distance — from the center of the rivet to the edge of the sheet — is usually set at about 2.5 times the rivet diameter, with 2 times the diameter as the minimum. Too close to the edge and the sheet can tear out.

Rivet spacing, or pitch — the distance between rivet centers — is typically about 4 times the diameter, within a usual range of 3 to 6 times. Closer spacing is stronger but risks cracking between holes; wider spacing can let the joint gap.

For example, a 1/8-inch rivet wants about 0.31-inch edge distance and 0.5-inch spacing. This calculator gives both from the rivet diameter it recommends.

A rivet’s single-shear strength is the area of its cross-section times the material’s ultimate shear strength. The area is pi over 4 times the diameter squared, so strength rises with the square of the diameter.

Ultimate shear strengths are about 30,000 psi for 2117-T4 (AD) aluminum, 41,000 for 2024-T4 (DD) aluminum, 42,000 for steel, and 65,000 psi for stainless. A bigger or stronger rivet carries more load.

For example, a 1/8-inch AD rivet has a single-shear strength around 370 pounds. This calculator reports the single-shear strength per rivet for the size and material you pick. Double shear — a rivet cut on two planes — is about twice this.

Divide the total load the joint must carry by the single-shear strength of one rivet, then round up. That gives the minimum number of rivets, before any safety factor.

For example, a 2,000-pound joint using 1/8-inch AD rivets at about 370 pounds each needs at least six rivets, and more with a safety margin. The rivets are then spread along the joint at the recommended spacing.

This calculator gives the single-shear strength per rivet, so you can divide your joint load by it to estimate the count. For structural work, apply the safety factor and checks from the governing standard.

The letter codes identify aluminum rivet alloys by their driving and strength properties. AD rivets are 2117-T4 aluminum, the most common, driven as-is with an ultimate shear around 30,000 psi. DD rivets are 2024-T4, stronger at about 41,000 psi, but must be driven soon after heat treatment or kept chilled.

Steel rivets, around 42,000 psi, and stainless, around 65,000 psi, are stronger still and used where the extra strength or corrosion resistance is needed, though they are harder to drive.

Match the rivet material to the sheet to avoid galvanic corrosion and to the load. This calculator lets you pick the material and uses its shear strength for the per-rivet strength.

The diameter, length and drill sizes here follow the rules of thumb and hole clearances for solid rivets — the kind set by bucking or squeezing, common in aircraft and sheet-metal work.

Blind (pop) rivets, structural rivets, tubular rivets and self-piercing rivets work differently: they have their own grip ranges, hole sizes and strength ratings set by the manufacturer, and you should use those rather than the solid-rivet rules.

So use this calculator to size a solid rivet and to understand the general relationships; for a blind or structural rivet, size it from the maker’s data sheet instead.