Explains activity intensity, perceived exertion, and heart-rate context.
Health & fitness
One-repetition maximum
Enter your values below for a clear, instant result.
Your result
kg
FormulaEpley estimate: 1RM = weight × (1 + reps/30)
- Enter the known values.
- Apply the displayed formula.
- Review the result and supporting values.
Worked example: 80 kg for 8 reps estimates about 101.3 kg.
Estimate notice: This one-repetition maximum result is an estimate based only on the values and assumptions shown. Verify important decisions with the relevant official source or a qualified professional.
Educational estimate only—not medical advice. Individual health needs vary; consult a qualified clinician when making health decisions.
Understand the result before using it
One-repetition maximum uses weight lifted and repetitions to calculate its result. It uses a population-based health or fitness equation to produce an educational estimate from your measurements.
Formula, assumptions, and example
Formula
Epley estimate: 1RM = weight × (1 + reps/30)
Assumptions
- The entered weight lifted and repetitions are complete, valid, and use the units or format shown beside each field.
- Measurements are accurate and were taken using the method expected by the equation.
- Population averages are an acceptable starting point for this educational calculation.
Worked example
80 kg for 8 reps estimates about 101.3 kg.
When to use it
Good uses
- Understand a general screening measure or planning range.
- Track a consistent estimate over time while using the same method.
- Prepare an informed discussion with a qualified healthcare professional.
Limitations
Common mistakes to avoid
- Individual biology, pregnancy, age, medication, disability, training status, and clinical history may make the estimate unsuitable.
- The result cannot diagnose a condition or prescribe treatment, diet, exercise, or medication.
- Educational estimate only—not medical advice. Individual health needs vary; consult a qualified clinician when making health decisions.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Evidence-based context for energy and body-weight planning.
Questions about this calculation
What does the One-repetition maximum calculate?
One-repetition maximum uses weight lifted and repetitions to calculate its result. It uses a population-based health or fitness equation to produce an educational estimate from your measurements. The formula used is: Epley estimate: 1RM = weight × (1 + reps/30)
Which inputs affect the One-repetition maximum result?
The result uses weight lifted and repetitions. Changing any of these values can change the output, so enter them using the labels and units shown.
Is the One-repetition maximum result exact?
This one-repetition maximum result is an estimate based only on the values and assumptions shown. Verify important decisions with the relevant official source or a qualified professional.
When should I verify a One-repetition maximum result?
Verify it before any financial, health, academic, construction, safety, or engineering decision. Use the primary source or an appropriately qualified professional.
Clear answers, without the guesswork
1Enter your information
Use the fields above. Results refresh automatically as values change.
2Review the calculation
The formula and context explain how the result was reached.
3Save or share it
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