One Rep Max Calculator
Estimate your one-rep max (1RM) from a submaximal set using the Epley, Brzycki, and Lander formulas.
kg
reps
Estimated 1RM
Epley
116.7 kg
Brzycki
112.5 kg
Lander
113.7 kg
Average
114.3 kg
For general information only, not medical advice. Talk to a doctor before making health decisions based on this result. Terms
What is a one rep max calculator?
A one-rep-max (1RM) calculator estimates the maximum weight you could lift for a single repetition, based on a submaximal set (a weight you lifted for several reps). It's the standard way to track strength without risking a max-out attempt.
Formulas
Brzycki: w × 36 / (37 − r)
Lander: w × 100 / (101.3 − 2.67123 × r)
Example
Lifting 100 kg for 5 reps gives an estimated 1RM of about 112–117 kg depending on the formula (Brzycki 112.5, Lander 113.7, Epley 116.7) — a useful target for programming your next training block.
Common Use Cases
- Setting training weights as percentages of 1RM.
- Tracking strength progress over time.
- Planning progressive-overload programs safely.
FAQs
Which formula should I trust?
The three formulas agree closely for lower rep counts (1–5). They diverge as reps rise, so the average shown here gives a balanced estimate — treat it as approximate.
Are these estimates accurate?
They're good ballpark figures but not a substitute for a tested max. Always use conservative loads when training near your estimated 1RM.