Sports
One Rep Max Calculator
Estimate Epley 1RM, Brzycki 1RM, their average, and a percentage-based training maximum. The barbell visualization compares the lifted set, formula range, average estimate, and conservative training maximum.
Epley one-rep max-
Brzycki one-rep max-
Average estimated one-rep max-
Training maximum-
Planned repetitions across sets-
Planned load volume at entered weight-
Decision view
Submaximal set to training-max reference
Submaximal set to training-max referenceThe lifted set feeds two separate 1RM formulas; their range and average remain visible before the conservative training maximum.
Exact scenario comparisonRepetitions completed changes while all other entered assumptions remain constant.
| Repetitions completed | Epley one-rep max | Brzycki one-rep max | Average estimated one-rep max | Training maximum | Planned repetitions across sets | Planned load volume at entered weight |
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How to use One Rep Max Calculator
- Enter the external load lifted for a technically consistent set and the number of completed repetitions.
- Keep the repetition count within the range where the formulas remain meaningful and review the spread between estimates.
- Use the average or a conservative training maximum to program percentages while adjusting for exercise, equipment, readiness, and technique.
Calculator guide
Understanding One Rep Max Calculator
A one-repetition maximum estimate translates a submaximal set into a planning reference without requiring a true maximal attempt. Because formulas diverge as repetitions increase, this calculator shows both Epley and Brzycki estimates before averaging them.
Calculation method
How the calculation works
Calculate Epley and Brzycki estimates from submaximal weight and repetitions, average them, apply a training-max percentage, and use planned sets to expose total repetitions and load volume at the entered weight. Calculate Epley 1RM as weight × (1 + reps/30) and Brzycki 1RM as weight × 36/(37 − reps). Average the two estimates, then multiply by the entered training-max percentage.
Programming use
Use estimated 1RM as a moving reference
The value is most useful for comparing similar sessions and selecting sensible training loads.
Worked situations
Practical examples
- An 80 kg lift for eight repetitions produces an Epley estimate near 101.3 kg.
- The Brzycki estimate is near 99.3 kg, placing the two-formula average around 100.3 kg.
- At a 90% training-max setting, the working reference becomes roughly 90.3 kg before practical plate rounding.
Better inputs
Useful tips
- Use a set stopped by genuine repetition capacity with stable technique; an easy set with many repetitions in reserve understates 1RM.
- Compare estimates within the same exercise and equipment setup rather than across machines, bars, ranges of motion, or techniques.
- Round programmed loads to available plates and adjust for readiness rather than treating the estimate as a required performance.
Before relying on the result
Limitations and common mistakes
- Prediction error increases with high-repetition sets and differs by exercise, athlete, training age, fiber profile, and technique.
- The model does not know repetitions in reserve, tempo, range of motion, assistance, fatigue, pain, or equipment calibration.
- Maximal and near-maximal lifting carries injury risk and may be inappropriate without qualified coaching or medical clearance.
Reference
Key terms
- 1RM
- Maximum load that can be lifted once with the required technique under specified conditions.
- Submaximal set
- Set performed with a load below true one-repetition maximum.
- Training maximum
- Conservative percentage of estimated 1RM used as a programming reference.
- Repetitions in reserve
- Estimated number of additional technically acceptable repetitions that could have been completed.
Important note
Calculated from the entered performance values using the displayed method. Health, fitness, terrain, weather, equipment, and event conditions can change real-world outcomes.
Frequently asked questions
Should I test a true 1RM?
Not necessarily. Submaximal estimates can support programming with less fatigue and risk, though they still contain uncertainty.
Which formula is correct?
Neither is universally exact. Showing both reveals a reasonable formula spread for the entered set.
Why use a training maximum below estimated 1RM?
A conservative reference allows room for fatigue, technique, and day-to-day variation.
Can I use this for bodyweight exercises?
Only if the effective system load is defined consistently; body mass and external assistance or load complicate the input.