One-Rep Max Calculator
Estimate your one-rep max from a recent set of weight × reps. Uses Epley, Brzycki, Lander, Lombardi, and Mayhew formulas — best accuracy with 1-6 reps.
Per-formula estimates
- Epley117 kg
- Brzycki113 kg
- Lander114 kg
- Lombardi117 kg
- Mayhew119 kg
Training percentage table
- 95%110 kg1-2 reps
- 90%104 kg3-4 reps
- 85%98 kg5-6 reps
- 80%93 kg7-8 reps
- 75%87 kg9-10 reps
- 70%81 kg11-12 reps
- 65%75 kg13-15 reps
- 60%70 kg16-18 reps
- 55%64 kg20+ reps
- 50%58 kg20+ reps
"5×5 at 80%" = the weight in the 80% row, 5 sets of 5 reps. Most strength programs prescribe loads this way.
How to use
- 1
Pick your weight unit (kg or lb).
- 2
Enter the weight you lifted for a recent working set.
- 3
Enter how many clean reps you completed. Use a set where you stopped 0-1 reps from failure.
- 4
The calculator returns the average of 5 standard formulas. Best accuracy with 1-6 reps — high-rep sets test endurance more than max strength.
Frequently asked questions
Brzycki and Epley are the most cited in coaching practice and the most accurate for the typical 3-10 rep range. Lombardi tends to overestimate for very low reps. Mayhew is more accurate for trained lifters. Averaging across all five reduces the worst-case error from any single formula.
Estimating 1RM from 20 reps is mostly testing your muscular endurance, not your max strength. The relationship between reps and percentage of 1RM is non-linear and varies between people. For best results, use a recent set of 3-6 reps near failure.
Only with a spotter, proper warm-up (a 6-step ramp from light singles is standard), and good technique. Maxing out is genuinely useful for periodisation and competition. Doing it without spotters on bench, squat, or overhead press is how injuries happen.
Intermediate trained adult man benchmarks roughly: bench 1× bodyweight, squat 1.5× bodyweight, deadlift 2× bodyweight. Women's relative benchmarks are similar in pattern but with different absolute numbers due to lower upper-body muscle mass on average. These are intermediate — not beginner, not elite.
Most strength programs prescribe sets at percentages of 1RM. Knowing your estimated 1RM lets you set working loads — e.g. '5×5 at 80% of 1RM' becomes a concrete weight to put on the bar.
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Source: Epley 1985, Brzycki 1993, Lander 1985, Lombardi 1989, Mayhew et al. · Last verified 2026-06. This tool provides estimates only and is not legal, tax or financial advice. Always verify your specific situation with the relevant UAE authority or a licensed advisor before taking action.