One Rep Max Calculator - Free 1RM Calculator
Calculate your one-repetition maximum (1RM) for any lift including bench press, squat, deadlift, and more. Estimate maximum strength based on weight and reps using proven formulas (Epley, Brzycki, Lander). Get personalized training zones for power, strength, hypertrophy, and endurance.
One Rep Max Calculator
Calculate your maximum strength and training zones
What is One Rep Max (1RM)?
Your 1RM is the maximum weight you can lift for one complete repetition. This calculator estimates your 1RM based on a weight you can lift for multiple reps, helping you plan training programs safely.
Enter 1-20 reps for accurate results
These calculations are estimates based on submaximal lifts. For accurate 1RM testing, work with a qualified coach or trainer. Always prioritize proper form and safety over heavy weights.
How the One Rep Max Calculator Works
The One Rep Max (1RM) Calculator estimates the maximum weight you can lift for a single repetition of a given exercise. Instead of risking injury by attempting a true 1RM, you can use a weight you can lift for multiple repetitions (a submaximal lift) to get a reliable estimate. This calculator uses several well-established scientific formulas to provide a comprehensive and averaged result.
The process is simple:
- Enter Your Lift: Input the weight you lifted and the number of repetitions you completed (ideally between 2 and 10 for best accuracy).
- Multiple Formulas: The calculator processes your input through several popular formulas (Epley, Brzycki, Lombardi, etc.). Each formula has a slightly different mathematical model, which is why they produce slightly different results.
- Averaged Result: The main result shown is the average of all these formulas, providing a balanced and generally more reliable estimate than any single formula alone.
- Training Zones: Based on your estimated 1RM, the tool automatically calculates your training zones for different goals like strength, muscle growth (hypertrophy), and endurance. This allows you to structure your workouts with appropriate weights for your specific objectives.
Tips for Training with 1RM
1. Use It for Programming
Your 1RM is not just for bragging rights; it's a foundational metric for a structured training program. Use the "Training Percentages" table to plan your workouts. For example, if your program calls for a set of 5 reps at 85% of your 1RM, you can instantly find the correct weight to use.
2. Choose the Right Rep Range
The formulas are most accurate for lifts performed in the 2-10 rep range. A lift performed for 15 or 20 reps is more a measure of muscular endurance and will produce a less accurate 1RM estimate. For best results, use a weight you can lift with good form for about 5 reps.
3. Re-test Periodically
As you get stronger, your actual 1RM will increase. Re-calculate your estimated 1RM every 4-6 weeks to ensure your training weights remain challenging and effective for continued progress.