Calculate flat washer weight in grams or kg: pick a metric size (M3 to M30) and a material such as mild steel, or enter your own washer dimensions.

Standard metric flat washer (ISO 7089 / DIN 125). Picking a size fills the dimensions; edit them for other washers.

Zero models a solid disk.

Optional settings
Blank = one washer.

Flat Washer Weight Formula

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

FWW = ฯ€ร—(OD2/4 – ID2/4) ร— T ร— 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/in3)

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.
    • Assume carbon steel at approximately 0.2836 lb/inยณ (about 7.85 g/cmยณ).
  5. Finally, calculate the Flat Washer Weight using the formula above: 

FWW = pi*(OD2/4 – ID2/4) * T * d

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

FWW = ฯ€/4 ร— (10ยฒ โˆ’ 5ยฒ) ร— 2 ร— 0.2836 โ‰ˆ 33.41084 lb for one washer.

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; assumed density = 0.2836 lb/inยณ

Test your knowledge and check your answer with the calculator.

FWW = ฯ€/4 ร— (30ยฒ โˆ’ 20ยฒ) ร— 5 ร— 0.2836 โ‰ˆ 556.84730 lb for one washer. Multiply single-piece mass by quantity for a batch. Inverse mode uses a known single-piece mass to solve thickness.