🏋️ Free Tool

1RM Calculator

Estimate your one-rep max using 4 scientifically validated formulas. Enter the weight lifted and reps performed to calculate your 1RM.

Weight lifted

Reps performed

1530

Unit

📖 What is 1RM?

The 1RM (One Repetition Maximum) is the maximum weight you can lift for a single repetition with proper form. It's the most widely used metric for measuring absolute strength and serves as the foundation for prescribing training loads. Knowing your 1RM allows you to program training sessions with precise percentages, optimizing strength and hypertrophy gains.

🧮 How to use this calculator

Enter a weight you can lift for multiple reps (ideally between 3 and 10 reps). The calculator uses 4 scientifically validated formulas — Epley, Brzycki, Lander, and Lombardi — and averages them for a more accurate estimate. Use the percentage table to program your training sessions at different intensities.

⚠️ Safety Tips

• Always warm up progressively before testing heavy loads. • Use a spotter for compound lifts like bench press and squats. • These formulas provide estimates — actual 1RM can vary ±5-10%. • Estimates are most accurate with 3-10 reps. Above 10, accuracy decreases. • Don't test actual 1RM too often — once every 4-8 weeks is sufficient.

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