One Rep Max Calculator
Estimates the maximum weight you could lift for one repetition from a submaximal set using the Epley formula, cross-checked against Brzycki and Lombardi. Includes a training-load table mapping %1RM to rep ranges for programming.
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Estimated One Rep Max (Epley)
116.7 kg
100 kg × 5 reps · average of 3 formulas: 115.5 kg
- Epley: w × (1 + r/30)
- 116.7 kg
- Brzycki: w × 36/(37 − r)
- 112.5 kg
- Lombardi: w × r^0.10
- 117.5 kg
- Formula average
- 115.5 kg
- 90% training weight
- 105.0 kg
- 70% training weight
- 81.7 kg
Epley calculation
- 1Inputweight = 100.0 kg, reps = 5
- 2Apply formula1RM = 100.0 × (1 + 5/30) = 100.0 × 1.2 = 116.7 kg
- 3Cross-checkBrzycki 112.5 · Lombardi 117.5 kg
Training loads from your 1RM
Rep counts are typical for trained lifters — they vary by exercise and individual fiber profile.
Testing a true 1RM is a skill — use a spotter, warm up thoroughly, and never max out with poor form. Estimates are least accurate above 10 reps. Estimates for informational purposes only — not medical advice.
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Formula
Epley: 1RM = w × (1 + reps/30) · Brzycki: 1RM = w × 36/(37 − reps) · Lombardi: 1RM = w × reps^0.10
- • Record a set you completed with good form — 1 to 10 reps gives the best estimates.
- • Apply Epley (the primary formula) and compare with Brzycki and Lombardi.
- • Program training at 60–95% of the estimate using the load table.
Pro tips
- • Use a 3–5 rep set for the most accurate extrapolation — the formulas diverge at high rep counts.
- • 1RM is exercise-specific: a bench press max says nothing about your squat.
- • Re-test every 4–8 weeks; strength gains of 2–5% per month are realistic for intermediates.
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