Calculate rivet length from grip and shank diameter with the 1.5 × diameter rule, estimate rivet diameter from sheet thickness, or check blind rivet grip.

Total grip is the thickness of every layer the rivet passes through.

Shop-head allowance and stock increment
The default 1.5 × diameter is a common solid-rivet allowance. Use the governing installation specification.

Default: 1/16 in. Results round upward to a multiple of this increment; verify actual stock availability.

Rivet Length Formula

The following rule of thumb estimates solid-rivet length with a shop-head formation allowance of 1.5 shank diameters. Use the allowance required by the governing drawing or installation specification. Rivet length includes a flush head; protruding-head length is measured beneath the manufactured head. Thicker material stacks can require a different allowance.

RL = (T1 + T2 + 1.5 × D)
  • Where RL is the Rivet Length (in)
  • T1 is the thickness of material 1 (in) 
  • T2 is the thickness of material 2 (in) 
  • D is the diameter of the rivet stem (in) 

To estimate solid-rivet length with the default allowance, add the thicknesses of every material layer, then add one and a half times the shank diameter. The calculator can round this theoretical length upward to a multiple of an entered stock increment; verify actual stock and specified length because an overly long rivet can bend during driving. Blind rivets use their manufacturer’s stated grip range instead of this solid-rivet allowance.

How to Calculate Rivet Length?

The following two example problems outline the steps and information needed to calculate the Rivet Length.

Example Problem #1

  1. First, determine the thickness of material 1 (in).
    • The thickness of material 1 (in) is calculated to be 2.
  2. Next, determine the thickness of material 2 (in).
    • The thickness of material 2 (in) is measured to be 3.
  3. Next, determine the diameter of the rivet stem (in).
    • The diameter of the rivet stem (in) is found to be 4.
  4. Finally, calculate the Rivet Length using the formula above: 

RL = (T1+T2 + 1.5*D)

The values provided above are inserted into the equation below and computed.

RL = (2+3 + 1.5*4) = 11 (in)

Example Problem #2

The variables required for this problem are provided below:

thickness of material 1 (in) = 5

thickness of material 2 (in) = 6

diameter of the rivet stem (in) = 8

Test your knowledge using the equation and check your answer with the calculator.

RL = (T1+T2 + 1.5*D) = (in)