How to use it
- Enter your best recent quality set weight and reps.
- Review the estimated one-rep max and generated percentage loads.
- Use those percentage loads to plan top sets and back-off work.
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Strength
1RM Calculator
Use your performed set to estimate one-rep max and instantly map practical percentage-based working loads.
Free to use. No account required.
- InputYour numbers
- EstimateA practical result
- DecisionYour next move
Live calculator
Enter the inputs. Keep the decision yours.
The estimate updates from the values below. Use it as a clear starting point, then apply the context that matters to you.
Enter weight and reps for a set performed to failure (or near failure). The calculator uses the Epley formula which is most accurate for rep ranges under 10. Use the generated table to quickly find working weights for percentage-based programs.
Start typing to see exercise suggestions from the library.
Live calculation using the Epley formula: 1RM ~= weight x (1 + reps / 30).
Estimated 1RM
Enter weight and reps to see an estimate.
What to enter
- Use a set from the last 7-14 days for best relevance.
- Most formulas are more reliable when reps are in the 1-10 range.
- Keep units consistent (all lbs or all kg) for every field.
How to read the result
- Treat the estimate as a planning anchor, not an exact lab value.
- If day-to-day readiness is low, reduce programmed percentages slightly.
- Recalculate after notable performance change to keep loads current.
Worked example
Weekly strength progression setup
- Scenario
- A client hits 225 x 5 this week and needs next-week loading targets.
- Workflow
- Run 225 x 5, review estimated 1RM, then pull 80%, 85%, and 90% targets.
- Decision
- Set the top set from 85-90% and assign back-off volume from 75-82%.
Good to know
Frequently asked questions
Is this 1RM estimate exact?
No. It is an estimate for programming decisions, and real performance can vary by recovery, skill, and exercise.
What rep range gives the best estimate?
Lower-rep quality sets usually produce more stable estimates, commonly between 1 and 8 reps.
How often should I recalculate 1RM?
Recalculate whenever a client hits a clear performance change or when a new block begins.
One connected coaching system
Keep the result connected.
Keep programming, nutrition, progress, and follow-up connected after the calculation.
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