One-Rep Max Calculator
Quick answer
Enter the weight you lifted and how many reps you completed to estimate your one-rep max (1RM) — the most you could lift for a single rep — using the Epley and Brzycki formulas, plus training percentages.
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The two formulas
Epley: 1RM = weight × (1 + reps ÷ 30)
Brzycki: 1RM = weight × 36 ÷ (37 − reps)
Most accurate for sets of 2–10 reps. We show the average of both formulas.
Worked example
- 1
You squat 60 kg for 8 reps.
- 2
Epley: 60 × (1 + 8/30) = 76.0 kg.
- 3
Brzycki: 60 × 36 ÷ 29 = 74.5 kg.
- 4
Estimated 1RM ≈ 75 kg; 80% training weight ≈ 60 kg.
Using your one-rep max
| Your result | Category | What it means |
|---|---|---|
| 85–95% of your 1RM | Strength (1–5 reps) | Builds maximal strength. Use sparingly, only after a thorough warm-up and with good technique. |
| 65–80% of your 1RM | Hypertrophy (6–12 reps) | The classic range for muscle growth. |
| 50–65% of your 1RM | Muscular endurance (12+ reps) | Builds endurance and movement skill — great for technique practice. |
Standard percentage-based loading for strength goals (NSCA-style).
Frequently asked questions
Sources & further reading
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Open calculatorThis calculator provides general estimates for informational purposes only and is not medical advice. For personal guidance, consult a qualified healthcare provider.