Sport & running
How do you calculate your one-rep max from submaximal reps?
Estimate your 1RM from weight and reps with the Epley formula, plus a loading table.
Quick answer
Your one-rep max (1RM) is the heaviest weight you can lift once with proper form — and you don’t need to actually test it to know it. Formulas like Epley’s, used by this calculator, estimate it accurately from any set taken close to failure: lift 80 kg for 8 clean reps and your bench 1RM is around 101 kg. The estimate is most reliable up to 10-12 reps.
Estimated one rep max (1RM)
101.3 kg
| % of 1RM | Load | Typical reps |
|---|---|---|
| 95% | 96.3 kg | ~2 |
| 90% | 91.2 kg | ~4 |
| 85% | 86.1 kg | ~6 |
| 80% | 81.1 kg | ~8 |
| 75% | 76 kg | ~10 |
| 70% | 70.9 kg | ~12 |
| 65% | 65.9 kg | ~15 |
| 60% | 60.8 kg | ~18 |
Epley formula: 1RM = weight × (1 + reps ÷ 30). Above 12 reps the estimate loses accuracy. Only test your real max with a spotter.
How it works
Why does it matter? Because nearly every serious strength program prescribes loads as percentages of 1RM: 5×5 at 75%, hypertrophy work at 65-75%, heavy triples at 90%. The loading table above converts your estimate into exact weights for each percentage, so you can run any program without guessing. Re-test every 4-6 weeks — as your reps at a given weight increase, your estimated max rises with them.
Frequently asked questions
How accurate are 1RM formulas?+
Within 2-5% for sets of 2-6 reps, slightly less accurate up to 10-12 reps, unreliable beyond that. Accuracy also varies by exercise: estimates work best on bench press and squat, a bit worse on deadlift where technique breaks down earlier. Treat the number as an excellent working estimate, not a certified record.
Should beginners test their real 1RM?+
No — and honestly, most intermediates don’t need to either. A true max attempt with immature technique is where injuries happen, and the information adds nothing a formula can’t give you. Test a real 1RM only if you compete in powerlifting, always with a spotter or safety pins, after months of consistent technique work.
What percentage of 1RM should I train at?+
Depends on the goal: 85-95% in low reps (1-5) builds maximal strength, 65-80% for 6-12 reps is the classic hypertrophy zone, and 50-65% for 15+ reps trains endurance. Effective programs mix these ranges. The loading table above gives you the exact kg for each percentage of your estimated max.
Why did my 1RM estimate go down even though I train?+
Usually it’s measurement noise, not lost strength: you estimated from a different rep range, tested while fatigued, or counted a grinding rep as clean. Estimate from the same exercise, same rep range (ideally 3-6 reps), in a fresh state. If the decline persists for weeks, look at recovery: sleep, calories and accumulated fatigue.
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