Relative Strength Calculator
How strong are you for your size? See your lift as a multiple of your bodyweight, and what the same strength would look like at other bodyweights.
Your details
Your results
Enter your max and your bodyweight.
Strength-to-bodyweight ratio
× bodyweight
Allometric score (lift ÷ bodyweight0.67, in kg)
| Bodyweight | Equal lift | Ratio |
|---|---|---|
| 60 kg | ||
| 70 kg | ||
| 80 kg | ||
| 90 kg | ||
| 100 kg | ||
| 110 kg | ||
| 120 kg | ||
| 130 lb | ||
| 150 lb | ||
| 170 lb | ||
| 190 lb | ||
| 210 lb | ||
| 230 lb | ||
| 260 lb |
How to use it
- Enter your max for any lift. No recent max? Estimate it with the One Rep Max Calculator.
- Enter your bodyweight.
- Read your strength-to-bodyweight ratio and your allometric score.
- The table shows the lift that would be equally strong at other bodyweights. Your own row is highlighted.
How it's calculated
Ratio. Lift ÷ bodyweight. A 140 kg squat at 80 kg bodyweight is a ratio of 1.75.
Allometric score. Lift ÷ bodyweight^0.67. Muscle strength depends mostly on a muscle’s cross-sectional area, and area grows with mass to the power 2/3 (about 0.67) when body shape stays similar. Jaric (2002) recommends this exponent for comparing strength between people of different sizes.
Equal lift at other bodyweights. Keeping the allometric score the same and solving for the lift:
lift at new bodyweight = your lift × (new bodyweight ÷ your bodyweight)^0.67
Example: 140 kg at 80 kg bodyweight equals about 162.5 kg at 100 kg bodyweight, a lower ratio (1.63 instead of 1.75) but the same strength for the size. Results are rounded to 2.5 kg or 5 lb.
Limits. The 0.67 exponent assumes people of different sizes have similar body shape and composition. Two lifters at the same bodyweight but with different body fat aren’t separated by any of these measures. Powerlifting formulas such as Wilks and DOTS use their own curves, fitted to competition results.
Sources
- Jaric, S. (2002). Muscle strength testing: use of normalisation for body size. Sports Medicine, 32(10), 615–631.
- Vanderburgh, P. M., & Batterham, A. M. (1999). Validation of the Wilks powerlifting formula. Medicine & Science in Sports & Exercise, 31(12), 1869–1875.
Questions
What is relative strength?
Strength compared with your bodyweight. Lifting 100 kg means more at 70 kg bodyweight than at 110 kg. The simplest measure is your lift divided by your bodyweight.
Why isn't a simple ratio fair?
Strength doesn't grow as fast as bodyweight. Double your size and your muscles' cross-section, which drives strength, only grows by about 1.6 times. So heavier lifters tend to have lower ratios, even when they're just as strong for their size.
What is an allometric score?
Your lift divided by bodyweight to the power 0.67. That exponent matches how muscle strength scales with size, so it compares lifters of different bodyweights more fairly than a ratio. The number itself has no everyday meaning; it's for comparing.
How do I know if my ratio is good?
That depends on the lift, your age and your sex. The Strength Standards Calculator compares your squat, bench and deadlift ratios with published data for people like you.
Updated November 9, 2026.