One-Rep Max Calculator — Your one-rep max (1RM) is the heaviest weight you can lift for a single rep with good form. You rarely actually test it — going to true failure is fatiguing and risky. Instead, you do a set of 3-8 reps at a submaximal weight and use a formula to estimate what you could have done for 1 rep.
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Estimates come from predictive formulas, not actual lifts — treat them as guidance, not medical or training advice. Testing a true one-rep-max carries injury risk; use a spotter and progress gradually.
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One-Rep Max Calculator是什么？
Your one-rep max (1RM) is the heaviest weight you can lift for a single rep with good form. You rarely actually test it — going to true failure is fatiguing and risky. Instead, you do a set of 3-8 reps at a submaximal weight and use a formula to estimate what you could have done for 1 rep.
The two most common formulas are Epley (1RM = weight × (1 + reps/30)) and Brzycki (1RM = weight × 36 / (37 − reps)). Both work well in the 1-10 rep range; both overestimate above 10 reps. The tool defaults to the average of the two, which is the most accurate single estimate.
使用方法
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Enter a weight you actually lifted
A set that challenged you but did not fail. Don't sandbag — use the real number.
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Enter the rep count
How many clean reps you got. Stop counting at the first one that started to slow or shift form.
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Pick a formula
Average is the most accurate. Epley tends to estimate slightly higher; Brzycki slightly lower.
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Read the working weights
50% / 60% / 70% / 80% / 90% of your estimated 1RM for warm-ups and working sets.
示例
Bench press: 5 reps at 100 kg
Average of Epley and Brzycki formulas.
结果： Estimated 1RM ≈ 112.5 kg; 80% = 90 kg; 90% = 101.3 kg
Squat: 3 reps at 140 kg
Epley formula only.
结果： Estimated 1RM ≈ 154 kg; 70% = 107.8 kg; 90% = 138.6 kg
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Last reviewed: 2026-09-25