Strength · Bodyweight
Relative strength calculator.
Your lift as a multiple of bodyweight, and a size-adjusted score that lets you compare lifters of different weights.
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What is relative strength?
Relative strength is how much you lift compared with your size. The simplest version divides the lift by bodyweight. That ratio favours lighter people, because strength grows more slowly than body mass. Jaric (2002) reviewed this in Sports Medicine and recommended an allometric index, S = force / body massb, with b = 0.67 for muscle force measured on a dynamometer (b = 1 for torque). Applying the same exponent to a barbell lift is an extension of that recommendation, not something the paper tested, so read the score as a rough size-adjusted comparison. For competition scoring, use the Wilks, DOTS or IPF GL formulas in the powerlifting points calculator.
Worked example. A 200 kg lift at 80 kg bodyweight is 2.5 x bodyweight, with a size-adjusted score of 10.62. At 75 kg, keeping the same score needs 191.6 kg (2.55 x bodyweight), so a lighter lifter can lift less in absolute terms and score the same.
Frequently asked questions
What is relative strength?
Strength compared with body size, most simply the weight lifted divided by bodyweight. A 200 kg lift at 80 kg bodyweight is 2.5 times bodyweight.
Why not just divide by bodyweight?
Because strength does not rise in proportion to body mass, so a plain ratio favours lighter people. An allometric score divides by bodyweight raised to a power below 1.
Where does 0.67 come from?
Jaric 2002 recommends an allometric parameter of 0.67 for muscle force and 1 for muscle torque when normalising strength for body size.
Is this the same as Wilks or DOTS?
No. Those are fitted formulas for powerlifting totals. This is the simple bodyweight ratio plus the single-exponent allometric index.
Is there a good or bad ratio?
This tool does not grade your score. We did not find a peer-reviewed or openly licensed table of bodyweight multiples for novice, intermediate and advanced lifters, so we do not show one.
Sources
Checked
The allometric formula and exponents (0.67 for force, 1 for torque) are from the paper's abstract. The paper covers dynamometer tests; using 0.67 on a barbell lift is our application, not a tested result. Runs entirely in your browser; nothing you type is sent or stored.
Scope
Education only, not medical advice or personal coaching. Training carries injury risk: use a spotter or safeties for heavy lifts, stop if you feel sharp pain, and check with a clinician before starting a programme if you have a health condition, are pregnant or are returning from injury.