One-Rep Max (1RM) Calculator
One-Rep Max (1RM) Calculator Overview
Estimate your maximum lifting capacity for any exercise.
The One Rep Max (1RM) Calculator estimates the maximum weight you can lift for a single repetition based on a set of multiple reps. Measuring a true 1RM can be dangerous and taxing; this calculator allows you to test your strength safely using sub-maximal loads.
It calculates results using the industry-standard Epley and Brzycki formulas and provides a full percentage table (50-95%) so you can plan your hypertrophy or strength training cycles.
How to Use One-Rep Max (1RM) Calculator
- Enter the weight you lifted.
- Enter the number of repetitions performed (1-12).
- View your estimated 1RM.
- Consult the percentage table for your training weights.
Frequently Asked Questions
- How accurate is a 1RM calculator?
- It is very accurate for reps between 1 and 5. As reps increase (e.g., above 10), the accuracy decreases because endurance becomes a factor.
- Why do I need to know my 1RM?
- Many strength programs assign weights based on percentage (e.g., 'Do 5 sets of 5 at 75% of 1RM'). This tool gives you that number.
- Which formula is better?
- The Epley formula is slightly more aggressive (higher max), while Brzycki is more conservative. We show the average to give you a balanced estimate.
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