Health & Fitness calculator
One Rep Max Calculator
Estimate your one-rep max from a submaximal lift.
About the one rep max calculator
The one rep max calculator estimates your maximum lift from a submaximal set using the Epley formula.
How to use this calculator
- 1
Enter weight lifted
Enter the weight you lifted.
- 2
Enter reps performed
Enter how many reps you completed.
- 3
View results
See your estimated 1RM using multiple formulas.
How the calculation works
Epley formula: 1RM = weight × (1 + reps/30). Accurate for 1-10 reps, less reliable for higher reps.
Example: 100 kg for 5 reps: 1RM ≈ 117 kg.
Important health disclaimers
These calculators provide estimates based on population averages. Individual results vary based on genetics, body composition, medical conditions, and medications. Always consult a healthcare provider before starting a new diet or exercise program, especially if you have underlying health conditions.
Understanding body composition metrics
BMI doesn't distinguish muscle from fat. Body fat % is more accurate but depends on measurement technique. TDEE varies day-to-day based on activity. Macro targets are starting points — adjust based on your results, energy levels, and goals. Hydration needs increase with exercise, heat, and altitude.
Important limitations
This tool provides a mathematical estimate based only on the values entered. It does not account for regulations, taxes, lender fees, market conditions, or individual circumstances. Results are for planning purposes only — consult a qualified professional for regulated, medical, financial, or construction decisions.
Frequently asked questions about one rep max calculator
How accurate is the one rep max calculator?+
The calculation follows the displayed formula and retains full numeric precision before formatting the result.
Can I use the result professionally?+
Use it as a planning estimate. Confirm regulated, medical, financial, or construction decisions with a qualified professional.