Estimate your maximum strength for any major lift without attempting a dangerous one-rep max. Use this to program your workouts and track progress.
Your One-Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise (like a squat, bench press, or deadlift). Knowing your 1RM is essential for structuring your strength training program, as workouts are often based on percentages of your 1RM (e.g., lifting at 75% of your 1RM for 8-10 reps).
1RM = Weight × (1 + 0.0333 × Reps)
Example: 100 kg × (1 + 0.0333 × 5) = 116.7 kg (estimated 1RM).
Maintained by Live Fitness Check. Last updated: August 9, 2026. How we test our calculators .
Estimates the heaviest load that could be lifted for one repetition from a submaximal set.
The calculator applies its configured one-repetition-maximum prediction equation to the entered load and repetition count. The calculation uses weight lifted and repetitions completed.
Prediction accuracy decreases as repetitions rise and the estimate does not account for technique, fatigue, injury or exercise-specific differences. Use the number as an estimate and consider professional advice when the result may affect health, treatment, pregnancy, nutrition, exercise safety or another important decision.
