One Rep Max Calculator (1RM) — Epley Formula
Calculate your one-rep maximum (1RM) for any exercise using the Epley formula. Get your 1RM and a complete training percentage table for programming your workouts.
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Estimated 1RM
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Strength Level (Bench)
Training Percentage Table
| % of 1RM | Weight | Reps (Approx.) | Goal |
|---|
How to Use Training Percentages
Program your training sets based on percentages of your 1RM. Strength-focused training stays above 80%, hypertrophy work is in the 65–80% range, and endurance training uses lighter loads (50–65%). Rotate these zones across your training week for balanced development.
Frequently Asked Questions
What is the Epley formula for 1RM?
The Epley formula is: 1RM = weight × (1 + reps/30). For example, if you lifted 80 kg for 8 reps: 1RM = 80 × (1 + 8/30) = 80 × 1.267 = 101.3 kg. It is most accurate for 2–10 reps. For 1 rep, the lifted weight is your 1RM directly.
Which 1RM formula is most accurate?
For most people and rep ranges: Epley (used here) and Brzycki formulas are most commonly used and produce similar results at 5–8 reps. The Epley formula tends to slightly overestimate 1RM at higher rep counts (12+). For best accuracy, test with 3–6 rep sets.
Should I actually test my 1RM?
Testing your true 1RM carries injury risk, especially for beginners. Estimated 1RM from multi-rep sets is sufficient for programming training percentages. If you do test, ensure a thorough warm-up, have a spotter, and use proper form. Only advanced lifters should attempt true 1RM testing.
What percentage of 1RM should I train at?
For strength (1–5 reps): 85–100% 1RM. For hypertrophy/muscle growth (6–12 reps): 65–85% 1RM. For muscular endurance (12+ reps): 50–65% 1RM. This calculator provides the full percentage table so you can plan each set.
How often should I recalculate my 1RM?
Recalculate every 4–8 weeks or whenever you notice consistent improvements in your working weights. Your 1RM changes as you get stronger — using outdated numbers means training at incorrect intensities. Most competitive powerlifters recalculate every training cycle.