1rm Calculator
Calculate your one-rep max (1RM) based on the weight lifted and number of repetitions performed.
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isCalculator Editorial Team
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How to use this tool?
How to Use the 1RM Calculator
- Enter Weight Lifted (in kg): Type the weight you lifted (e.g., 80). Use increments of 0.5 if needed.
- Enter Repetitions: Type the number of reps performed (1 to 30). For a single rep, 1RM equals the weight entered.
- Click "Calculate 1RM": The button triggers the estimation.
- Read the Result: Your estimated one-rep max appears in kg, based on the Epley formula: 1RM = weight × (1 + reps/30).
Note: This calculator uses metric (kg). Ensure your inputs are in kilograms for accurate results.
Previous Results
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Frequently Asked Questions
1RM stands for one-repetition maximum, the maximum weight you can lift for one complete repetition of an exercise.
We use the Epley formula: 1RM = weight × (1 + reps/30). This provides a reliable estimate for most people.
Yes, the 1RM calculator works for any resistance exercise where you can perform multiple repetitions to failure.
