One Rep Max Calculator
Calculate your one rep max and training percentages for weightlifting.
Training Percentages
What is One Rep Max Calculator?
A one-rep max (1RM) calculator estimates the maximum weight you can lift for a single repetition, based on a set you completed with a known weight and reps.
Knowing your 1RM helps you set training loads for strength and hypertrophy programs.
How does the One Rep Max Calculator work?
The Epley formula estimates 1RM from a submaximal set.
The calculator also shows percentages of 1RM for different training goals (e.g. 70% for hypertrophy).
How to use the One Rep Max Calculator?
- Enter the weight you lifted.
- Enter the number of reps completed.
- The calculator shows your estimated 1RM and training percentages.
Example
Try the calculator with your own numbers
- Enter your values in the input fields above.
- Adjust the values to match your situation.
- The result updates instantly as you change the inputs.
Benefits of using the One Rep Max Calculator
- Set weights for strength programs.
- Track progress objectively.
- Avoid testing true 1RM repeatedly (safer).
Who should use the One Rep Max Calculator?
- People tracking their weight, fitness, and daily health numbers.
- Fitness enthusiasts planning workouts, calories, and protein intake.
- Parents monitoring their child's growth and development.
- Anyone preparing for a health check-up or fitness goal.
Tips for getting the most out of the One Rep Max Calculator
- Use your most recent measurements for the most accurate result.
- Re-check periodically as your weight, age, or activity level changes.
- Treat the result as a guideline, not a medical diagnosis — consult a professional for health decisions.
Frequently Asked Questions
How accurate is the 1RM estimate?
Within about 5% for sets of up to 10 reps. For higher reps, estimates become less reliable.
Should I test my true 1RM?
Only with proper warm-up and a spotter. Estimated 1RM is safer for most lifters.
Small daily decisions add up. Use this calculator to track your numbers and make healthier choices with confidence.
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