The One-Rep Max calculator calculates an estimate of your one-rep max, or the maximum weight you can lift for a given exercise. The calculator tells you the set weights for different rep ranges, making it easier to plan your next workout. Enter the weight you used for the exercise and the reps you did. Please note that the most reliable result from the calculator is obtained from exercises of less than 10 repetitions.
To get the most reliable one-repetition maximum estimate, perform a set of 2-10 repetitions of the desired exercise, where the last repetition is so challenging that the next repetition is no longer possible.
The calculator provides the set weights for the following repetitions based on the calculated one-repetition maximum:
| Reps | % 1RM |
|---|---|
| 1 | 100% |
| 2 | 95% |
| 4 | 90% |
| 6 | 85% |
| 8 | 80% |
| 10 | 75% |
When the number of repetitions is less than 10, the calculator calculates the one-repetition maximum and set weights using the Brzyck formula, as it gives the most accurate result possible for small repetitions.
where 1RM = one-rep max, w = weight lifted, r = reps
When the number of repetitions is higher, the calculator uses the Epley formula.
where 1RM = one-rep max, w = weight lifted, r = reps
Amarante do Nascimento, Matheus & Cyrino, Edilson & Nakamura, Fabio & Romanzini, Marcelo & Pianca, Humberto & Queiroga, Marcos. (2007). Validation of the Brzycki equation for the estimation of 1-RM in the bench press. Revista Brasileira de Medicina do Esporte. 13. 40e-42e.
Brzycki, Matthew. (1993). Strength Testing—Predicting a One-Rep Max from Reps-to-Fatigue. Journal of Physical Education, Recreation & Dance. 64. 88-90. 10.1080/07303084.1993.10606684.
MAXIMUM BASED ON REPS. National Strength and Conditioning Association Journal 6(6):p 60-60, December 1984.