One-Rep Max (1RM) Calculator
Result
One-Rep Max (1RM) Calculator Your one-rep max (1RM) is the most weight you can lift for a single repetition of an exercise. Rather than testing it directly, which is risky, this calculator estimates it from a lighter set: enter the weight you lifted and h — free online calculator.
Formula
- One-Rep Max (1RM) Calculator calculates its result from Weight Lifted, Repetitions. It uses the formula Epley: 1RM = Weight × (1 + Reps/30); Brzycki: 1RM = Weight / (1.0278 − 0.0278 × Reps); Lander: 1RM = Weight / (1.013 − 0.0267 × Reps). Change any input to recalculate the result instantly. This is an informational calculation and is not medical advice.
- The main inputs are Weight Lifted, Repetitions. Enter them in the units and format shown in the calculator.
- Use the measurement units shown beside each field. The result is an estimate and should be interpreted in context.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: One-Rep Max (1RM)
- Weight Lifted: 80
- Repetitions: 8
Using Weight Lifted = 80, Repetitions = 8, the calculated result is 100.0750562922.
Sample result: Calculating…
Frequently asked questions
What does the One-Rep Max (1RM) calculate?
One-Rep Max (1RM) Calculator Your one-rep max (1RM) is the most weight you can lift for a single repetition of an exercise. Rather than testing it directly, which is risky, this calculator estimates it from a lighter set: enter the weight you lifted and h — free online calculator.
Which values should I enter?
Enter Weight Lifted, Repetitions using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Epley: 1RM = Weight × (1 + Reps/30); Brzycki: 1RM = Weight / (1.0278 − 0.0278 × Reps); Lander: 1RM = Weight / (1.013 − 0.0267 × Reps).
Why might my result differ from another source?
Results can differ because measurement methods, rounding and assumptions vary. This calculator is an estimate and is not a medical diagnosis.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.