Calculate weight-to-length, length-to-weight, and weight per length for round wire, pipes, tubes, and flat rectangular materials by density.

Weight to Length Calculator

Convert total weight to total length, total length to total weight, or solve weight per length for common material shapes.

General Ratio
Round / Wire
Pipe / Tube
Flat / Rectangular

Enter any 2 values to calculate the missing one. This is the simplest weight to length converter.

Choose a material or enter a custom density, add diameter, then enter a total weight or a total length. Leave both blank to get weight per length only.

Choose a material or enter a custom density, add outside diameter and wall thickness, then enter a total weight or a total length. Leave both blank to get weight per length only.

Choose a material or enter a custom density, add width and thickness, then enter a total weight or a total length. Leave both blank to get weight per length only.

Weight to Length Formula

The following formula is used to calculate the Weight to Length. 

L = W / 9.81 / D / A
  • Where L is the Weight to Length (m)
  • W is the total weight (N) 
  • D is the density (kg/m^3) 
  • A is the cross-sectional area (m^2) 

To calculate the length from weight, divide the weight by 9.81, the density, and the cross-sectional area.

Weight to Length Conversion Table (Steel, ρ = 7850 kg/m³; A = 1.000 in²; g = 9.81 m/s²)
Weight (N) Length (m) Length (ft)
100.2010.660
250.5031.651
501.0063.301
751.5094.952
1002.0126.602
1503.0199.903
2004.02513.204
2505.03116.506
3006.03719.807
4008.04926.409
50010.06233.011
75015.09349.517
100020.12466.022
150030.18599.033
200040.247132.045
250050.309165.056
300060.371198.067
400080.494264.089
5000100.618330.112
10000201.236660.223
* Rounded to 3 decimals. Assumptions: steel (ρ = 7850 kg/m³), cross-sectional area A = 1.000 in² = 0.00064516 m², gravity g = 9.81 m/s². Formula: L = W / (ρ·g·A). Under these assumptions: ρ·g·A ≈ 49.683 N/m, so 1 N ≈ 0.020124 m ≈ 0.066022 ft.

How to Calculate Weight to Length?

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

Example Problem #1

  1. First, determine the total weight (N).
    • The total weight (N) is calculated to be : 500.
  2. Next, determine the density (kg/m^3).
    • The density (kg/m^3) is measured to be: 3.
  3. Next, determine the cross-sectional area (m^2).
    • The cross-sectional area (m^2) is found to be: 5.
  4. Finally, calculate the Weight to Length using the formula above: 

L = W/9.81/D/A

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

L = 500/9.81/3/5 = 3.397 (m)

Example Problem #2

The variables required for this problem are provided below:

total weight (N) = 600

density (kg/m^3) = 4

cross-sectional area (m^2) = 8

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

L = W/9.81/D/A = (m)