Calculate flat washer weight from outside diameter, inside diameter, thickness, material density, and quantity in metric or imperial units.

Required: outside diameter, inside diameter, thickness, material, and quantity.
Calculated result
Volume = π ÷ 4 × (outside diameter² − inside diameter²) × thickness. Weight = volume × density.

Flat Washer Weight Formula

The following formula is used to calculate the Flat Washer Weight. 

FWW = pi*(OD² / 4 - ID² / 4) * T * d

Variables:

  • FWW is the Flat Washer Weight (lbs)
  • OD is the washer outer diameter (in) 
  • ID is the washer inner diameter (in) 
  • T is the washer thickness (in) 
  • d is the material density (lbs/in^3)

How to Calculate Flat Washer Weight?

The following two example problems outline the steps and information needed to calculate the Flat Washer Weight.

Example Problem #1

  1. First, determine the washer outer diameter (in).
    • The washer outer diameter (in) is calculated to be : 10.
  2. Next, determine the washer inner diameter (in).
    • The washer inner diameter (in) is measured to be: 5.
  3. Next, determine the washer thickness (in).
    • The washer thickness (in) is found to be: 2.
  4. Next, determine the density.
    • This is given as 1.25 lbs/in^3.
  5. Finally, calculate the Flat Washer Weight using the formula above: 

FWW = pi*(OD^2/4 – ID^2/4) * T * d

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

FWW = pi*(10^2/4 – 5^2/4) * 2 * 1.25 = 147.462 (lbs)

Example Problem #2

The variables required for this problem are provided below:

washer outer diameter (in) = 30

washer inner diameter (in) = 20

washer thickness (in) = 5

Test your knowledge and check your answer with the calculator.

FWW = pI*(OD^2/4 – ID^2/4) * T * d = (lbs)