One-rep max calculator
Estimate your one-rep max from the weight and reps of a set taken close to failure.
Your estimated 1RM
112.5kg
100 kg × 36 ÷ (37 − 5) = 112.5 kg
Brzycki formula, valid up to 10 reps.
| % of 1RM | Weight | Approx. reps |
|---|---|---|
| 100% | 112.5 kg | 1 |
| 95% | 106.9 kg | 2–3 |
| 90% | 101.3 kg | 4–5 |
| 85% | 95.6 kg | 6 |
| 80% | 90 kg | 8 |
| 75% | 84.4 kg | 10 |
| 70% | 78.8 kg | — |
| 65% | 73.1 kg | — |
| 60% | 67.5 kg | — |
| 55% | 61.9 kg | — |
| 50% | 56.3 kg | — |
Below 75%, reps vary from person to person. Round to your plates with the plate calculator.
How it's calculated
Brzycki: 1RM = weight × 36 ÷ (37 − reps). It's the same formula Minthra uses for your e1RM on every set you log.
It's an estimate. Use it to choose loads, not as a target for one day.
Minthra does the math for you
In the app, your e1RM updates with every set you log and flags your records.
See availability
Coming soon to iPhone, Android and Apple Watch.