Strength to Weight Ratio Calculator

The lifting modes use lifted mass divided by body mass, as in the formula and examples below. They can also solve for lifted mass or body mass from a selected ratio.

The engineering alternatives use different definitions: material specific strength is strength stress divided by density, reported in kJ/kg; a component ratio is rated force divided by its self-weight (mass × 9.80665 m/s²), and is unitless. The self-weight length equivalent assumes an idealized uniform tensile member when interpreted as breaking length. These comparisons are not allowable-load calculations or design safety factors. Optional benchmarks compare the selected ratio basis (kJ/kg for material, unitless for lifting or components), including in reverse solves.

Strength-to-Weight Ratio Formula

The following formula is used to calculate the Strength-to-Weight Ratio. 

• Where SWR is the strength-to-weight ratio (unitless, e.g., kg/kg or lb/lb)
• S is the weight lifted (mass) (kg, g, or lb)
• W is the body weight (mass) (kg, g, or lb)

To calculate a strength-to-weight ratio, divide the weight lifted by body weight (use the same unit for both, or let the calculator convert).

How to Calculate Strength-to-Weight Ratio?

The following example problems outline how to calculate Strength-to-Weight Ratio.

Example Problem #1:

1. First, determine the weight lifted (use any mass unit).
   • The weight lifted is given as 400 lb.
2. Next, determine your body weight (use the same mass unit).
   • Your body weight is provided as 300 lb.
3. Finally, calculate the Strength-to-Weight Ratio using the equation above: 

SWR = S / W

The values given above are inserted into the equation below and the solution is calculated:

SWR = 400 / 300 = 1.33 (unitless, i.e., 1.33× bodyweight)

---

Example Problem #2: 

For this problem, the variables required are provided below:

weight lifted = 300 lb

body weight = 100 lb

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

SWR = S / W = ?