One Rep Max Calculator
1RM = Weight × (1 + Reps ÷ 30) (Epley formula)80×(1+5÷30)=80×1.167=93.4 kg
Free online tool
One Rep Max Calculator
Enter the weight you can lift and the maximum number of reps completed.
Instant calculation
One Rep Max Calculator
Enter the weight you can lift and the maximum number of reps completed.
Your result
Calculation
Your numbers stay in this browser. Nothing is uploaded or saved.
Three clear steps
How to use this calculator
- 01
Enter weight lifted
Type the weight you can lift for multiple reps.
- 02
Enter reps
Type the maximum number of repetitions you can complete.
- 03
See estimated 1RM
Calculate to see your estimated one-rep maximum.
The formula
How this calculation works
Epley formula estimates maximum strength from sub-maximal performance. Most accurate for 1-10 reps.
Check the method
Worked examples
Each example follows the same formula used by the calculator.
Lift 80 kg for 5 reps — estimated 1RM?
80×(1+5÷30)=80×1.167=93.4 kg≈ 93.4 kgCommon questions
Questions about this calculation
What is the One Rep Max Calculator?
The One Rep Max Calculator helps you estimate your one-repetition maximum lift from sub-maximal reps. Enter your values and select Calculate to get an instant result.
How is the result calculated?
Epley formula estimates maximum strength from sub-maximal performance. Most accurate for 1-10 reps.
Can you show an example?
Example: Lift 80 kg for 5 reps — estimated 1RM? — ≈ 93.4 kg.
Is my data saved when I use the One Rep Max Calculator?
No. All calculations run locally in your browser. Your inputs and results are never uploaded, stored or shared with anyone.
Is the One Rep Max Calculator free to use?
Yes. The One Rep Max Calculator is completely free. No account, sign-up or payment is required. It works on mobile, tablet and desktop.
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