One-Rep Max (1RM) Calculator
Enter weight lifted and reps to estimate your one-rep max (1RM) with the Epley formula.
Input Data
Kilograms
kg
Repetitions completed
次
Results
Estimated kg for a single rep
93.3kg
At a glance:Epley: 1RM = weight × (1 + reps ÷ 30). Most accurate for roughly 1-10 reps; error grows at higher reps.
Formula
oneRm = weightKg × (1 + reps ÷ 30).
How to Use
- Enter the weight you lifted and the reps you completed.
- Get the estimated one-rep max (1RM, kg) instantly.
Case Studies
80kg for 5 reps
1RM = 80 × (1 + 5/30) = 80 × 1.1667 = 93.3 kg.
FAQ
Is Epley accurate?
It is quite close for low-to-moderate reps (1-10); above ~15 reps it tends to overestimate, so use a lower rep set.
Why compute 1RM?
1RM is the baseline for training intensity — e.g. 70% for endurance, 85%+ for power.
Are there other formulas?
Brzycki and others exist; this tool uses the common Epley formula.
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References
Content reviewed by the Calculatorism editorial team. Results are for reference only; please refer to the relevant authorities for the official figures.