Free Weld Length Calculator

Calculate the minimum fillet weld length required to carry a given load based on weld size and allowable shear stress.

lbs
in
psi

Minimum Weld Length

0.00 in

Effective Throat0.177 in
Capacity per Inch3,712 lbs/in

Minimum Weld Length vs Applied Load

Fillet Weld Length

L = P / (t x Fv)

Where P is the applied load, t is the effective throat (0.707 x leg size for a 45-degree fillet), and Fv is the allowable shear stress on the weld metal. For E70 electrodes, Fv = 0.30 x 70,000 = 21,000 psi.

Example Calculation

10,000 lb load, 1/4-inch fillet weld, E70 electrode.

  1. 01Throat = 0.25 x 0.707 = 0.177 in
  2. 02Capacity = 0.177 x 21,000 = 3,713 lbs/in
  3. 03Min length = 10,000 / 3,713 = 2.69 in
  4. 04Use at least 3 inches of weld.

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