1RM & Strength Standards Calculator
Enter any set you've done - weight and reps - and see your estimated one-rep max. Compare your lifts to strength levels for your bodyweight, and plan your next training weights. Runs in your browser, nothing uploaded.
Learn more: 1RM formulas and strength scoring systems
Why six formulas instead of one
This calculator runs your weight and reps through six 1RM formulas (Epley, Brzycki, Mayhew, Lombardi, O'Conner, Lander) and averages them, rather than betting on a single equation. Each was fitted to a different dataset, and they behave differently as the rep count climbs.
Epley and O'Conner are linear in reps: weight × (1 + reps/30) and weight × (1 + reps/40). Lombardi is a power curve, weight × reps^0.1, which flattens out quickly. Mayhew uses an exponential term, while Brzycki and Lander are ratio formulas whose denominator shrinks as reps rise, so those two climb the steepest at high rep counts.
All six return the lifted weight itself at 1 rep, since a single-rep set is your 1RM and needs no estimating. They diverge as reps go up. A 100 kg set of 5 produces estimates from 112.5 kg to 119.0 kg, averaging 115.3 kg. The same 100 kg for 20 reps spans 134.9 kg on Lombardi to 211.8 kg on Brzycki.
That spread is why the tool clamps reps at 20, and why the averaged figure is the number worth reading. Test in the 3-6 rep range if you want the six formulas to agree with each other.
Wilks, DOTS, and why powerlifting scores don't match across federations
Wilks and DOTS both turn a powerlifting total plus bodyweight into one comparable score, each using a bodyweight polynomial so lifters of different sizes can be ranked against each other. They are not interchangeable, and this calculator reports both.
When the IPF moved on from Wilks in 2020 it adopted its own IPF GL Points formula, not DOTS, while DOTS was picked up separately by federations such as USPA and WRPF. rpe.training's explainer on Wilks, DOTS, and IPF GL walks through that split. It is why the same total and bodyweight can look like a different score depending on whose meet you are comparing against, so check which system your federation scores with.
FAQ
Which of the six 1RM formulas is most accurate for me?
It depends on the rep range you actually train in. Brzycki tends to track well from 2 to 6 reps and drifts high above 10, since fatigue and technique breakdown stop scaling neatly with rep count. The averaged estimate is a middle ground rather than a claim that any one formula is correct for you.
Why does a strength standards calculator need my bodyweight?
Absolute strength scales with body size, so a fixed target like "squat 100 kg" is not equally hard for a 60 kg and a 130 kg lifter. This calculator sorts bodyweight into five brackets (under 67.5 kg, 67.5-82.5, 82.5-97.5, 97.5-117.5, and above) and looks up separate Beginner through Elite thresholds for each, so your tier reflects strength relative to size.
Why does the female strength standard multiply the male numbers by 0.7?
That flat 0.7 scaling is a simplification in this calculator's standards table, not a claim that every lift and every lifter follows the same ratio. Published standards for women are normally built from separate datasets, so treat the tier here as an approximation.