Free strength calculators
Strength numbers, with the working shown
FFMI, powerlifting scores, barbell plates, RPE and one-rep max. Every result names its formula and source, in kilograms or pounds.
Standard plates: 25, 20, 15, 10, 5, 2.5, 1.25 kg on a 20 kg bar, or 45, 35, 25, 10, 5, 2.5 lb on a 45 lb bar.
Full plate calculator →Runs in your browser · nothing you type is sent anywhere · checked 12 November 2026 against the published formulas · How we check
Calculators
Strength
All strength calculators →FFMI calculator
Fat-free mass for your height, with the 1995 height adjustment labelled.
168 cm · 76 kg · 14% → 23.9Barbell plate calculator
Which plates go on each side, in kg or lb.
140 kg → 25 + 25 + 10 a sideRPE and RIR calculator
Estimated max from a set’s effort, and back-off sets.
100 kg × 5 @ RPE 8 → 123.3One-rep max calculator
Seven formulas side by side, and the spread.
100 kg × 5 → 112.5–119.0Powerlifting
All powerlifting calculators →Questions
Are my numbers sent anywhere?
No. The calculators run in your browser; what you type stays on your device.
Why do you show more than one formula?
Published formulas give different answers for the same set. We show them side by side, with the spread, so you can see how much they disagree.
Kilograms or pounds?
Both, on every calculator. Your choice is remembered in your browser.
What is coming next?
More strength tools first, then scores for military fitness tests and running paces.
Coming next
Planned, not live yet.
Military fitness · test score calculators built from the official tables.
Running · pace and race time tools.