Enter the weight and reps from any set to estimate your true one-rep max — plus a full training percentage chart.
Your one-rep max (1RM) is the heaviest weight you can lift for a single, full-effort repetition of a given exercise. It's the standard reference point for programming training percentages — most strength and hypertrophy programs prescribe work as a percentage of your 1RM rather than an absolute number, since it scales correctly as you get stronger.
Testing a true 1RM directly is fatiguing and carries some injury risk, so most lifters estimate it from a recent set instead. This calculator uses the Epley formula (1RM = weight × (1 + reps ÷ 30)), one of the most widely used estimation formulas in strength training.
Formula-based estimates are typically within 5-10% of your true max when calculated from sets of 10 reps or fewer. Accuracy drops as rep count climbs, since fatigue affects low-rep and high-rep sets differently.
The Epley formula: 1RM = weight × (1 + reps ÷ 30). It's one of the most widely used formulas for estimating one-rep max from submaximal sets.
For most lifters, no. Testing a true 1RM carries injury risk and isn't necessary for programming. An estimate from a recent set of 3-8 reps is accurate enough to plan training percentages.
Progress logs your sets, tracks PRs, and shows your real training percentages over time — no manual math required.
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