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
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.