How does the One Rep Max Calculator work?

Enter your values into the input fields, adjust any parameters, and click Calculate. The tool processes your input instantly and displays accurate results. All calculations happen locally in your browser for privacy and speed.

Is the One Rep Max Calculator free to use?

Yes, this tool is completely free with no signup required. Everything runs locally: Weight Lifted and Repetitions are processed on your device, never sent to a server — your data is never uploaded to any server, ensuring complete privacy and security.

Are the One Rep Max Calculator results accurate?

Yes, the calculator uses standard mathematical formulas and algorithms to ensure accurate results. Calculations are performed using JavaScript's built-in precision. For financial or medical decisions, always verify with a professional.

💪 One Rep Max Calculator

Home › 💪 One Rep Max Calculator

Estimate your one-rep max from weight and reps using Epley, Brzycki, and Lander formulas. | No registration · Data never leaves your browser

Zero dependencies · Works offline

💪 1RM Calculator

Weight Lifted (kg/lb)

Repetitions

Unit

📖 Formulas Used

This calculator uses the following formulas:

Epley: 1RM = Weight × (1 + Reps/30)
Brzycki: 1RM = Weight × 36 / (37 - Reps)
Lander: 1RM = 100 × Weight / (101.3 - 2.67123 × Reps)
Average: Average of the three formulas above

Updated: 2026-07-25

💪 One Rep Max Calculator

💪 1RM Calculator

📖 Formulas Used

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