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A practical one-rep max estimate scenario
For this example, use weight lifted of 80 kg, and completed repetitions of 5 reps. These are starting values, so replace them with numbers that match your situation.
Weight lifted: 25% lower
Change weight lifted to 60 kg while keeping the other example values the same.
Weight lifted: 25% higher
Change weight lifted to 100 kg while keeping the other example values the same.
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Quick answer
What does the One-rep max estimate calculate?
What rough one-repetition maximum follows from a submaximal lifting set? This calculator uses weight lifted, and completed repetitions to estimate estimated one-repetition maximum immediately in your browser.
With the values currently entered, the result is 202.1 lb — average one-rep-max estimate. It also shows epley estimate, brzycki estimate, and conservative 90% reference.
How to use the One-rep max estimate
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Weight lifted — entered in kg
- Completed repetitions — entered in reps
One-rep max estimate formula
Average of Epley (weight × (1 + reps ÷ 30)) and Brzycki (weight × 36 ÷ (37 − reps))
Assumptions
- The set used consistent technique and ended close to technical failure.
- The estimate is most useful for sets of 2–10 repetitions and varies by exercise and person.
Practical guide
One-rep max estimate example and edge cases
What rough one-repetition maximum follows from a submaximal lifting set? Let's use a concrete example, then look at the assumptions that can move the answer.
Example: A practical one-rep max estimate scenario
For this example, use weight lifted of 80 kg, and completed repetitions of 5 reps. These are starting values, so replace them with numbers that match your situation.
- Weight lifted
- 80 kg
- Completed repetitions
- 5 reps
Calculated result202.1 lbaverage one-rep-max estimate
Start with average one-rep-max estimate. Then check epley estimate, brzycki estimate, and conservative 90% reference to understand what sits behind the main result.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- Read the main result first. The supporting figures for epley estimate, brzycki estimate, and conservative 90% reference explain how the estimate is built.
- The method is Average of Epley (weight × (1 + reps ÷ 30)) and Brzycki (weight × 36 ÷ (37 − reps)). Keep the units consistent and use values from the same time period.
Edge cases worth checking
When weight lifted is unusual
The set used consistent technique and ended close to technical failure. Double-check this input before relying on the result.
When completed repetitions is uncertain
The estimate is most useful for sets of 2–10 repetitions and varies by exercise and person. Run a lower and higher value to see a useful range.
What changes the result most
Weight lifted
Measure weight lifted with the same unit shown beside the input. Convert first if your source uses another unit.
Completed repetitions
Change completed repetitions on its own first. This shows how strongly it affects the answer.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Weight lifted: 25% lower
60 kg151.6 lbaverage one-rep-max estimate
Weight lifted: 25% higher
100 kg252.6 lbaverage one-rep-max estimate
Completed repetitions: 25% higher
6 reps208.2 lbaverage one-rep-max estimate
Common mistakes
Check weight lifted
The set used consistent technique and ended close to technical failure. Make sure this matches the number you enter.
Keep completed repetitions consistent
The estimate is most useful for sets of 2–10 repetitions and varies by exercise and person. Use the same units and time period throughout the calculation.
Do not rely on one one-rep max estimate scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What rough one-repetition maximum follows from a submaximal lifting set?
Use it for activity planning, not medical diagnosis or individualized health advice.