Free Strength Calculator for Women and Men
Estimate Your Strength. Plan Your Next Session.
Enter the weight and repetitions from a recent completed set to estimate your one-rep max and see percentage-based reference loads.
Free to use. No account required. No max-out attempt needed.
Estimated one-rep max
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70%
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80%
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90%
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Your numbers appear after you calculate below.
One Rep Max Calculator
Enter a recent completed set. The result is an estimate, not a recommendation to attempt the displayed weight.
Your Strength Reference
Bodybuilder Models · One-Rep Max Calculator
Your estimate and reference loads will appear here after you calculate.
Want a Strength Reference Without Testing Your Limit?
A recent completed set can give you a starting estimate of your maximum strength. Use it to understand training percentages while keeping the limits of prediction in view.
Turn Your Last Set Into Useful Numbers
01
Estimate Your One-Rep Max
A single reference number from the weight and repetitions you already completed.
02
Review Percentage-Based Loads
Reference loads from 50% to 95%, rounded down to the plates you actually have.
03
Download Your Reference
Save or print your numbers to bring to your next session.
Your Estimate in Three Steps
1
Choose your lift and enter the weight.
Use the total external load, including the bar.
2
Enter the repetitions completed.
A whole number from 1 to 10 from a recent hard set.
3
Review your estimate and reference loads.
Then download or print them for your next session.
How the One-Rep Max Calculator Works
Epley equation (primary, 2–10 reps): 1RM = weight × (1 + reps ÷ 30). The reference-load table uses this unrounded estimate.
Completed single (1 rep): the calculator shows the weight you entered as a “Completed Single.” It is what you reported lifting once; it does not establish that it was your maximum.
Brzycki comparison (2–10 reps): 1RM = weight × 36 ÷ (37 − reps), shown in an expandable section. The two outputs are separate formulas; their difference is not a confidence interval.
Women and men: both equations use only the weight and repetitions you completed, so the same equation is used for women and men. The female/male selection is not a mathematical input.
An estimate, not a measurement: prediction equations approximate what a set suggests. Technique, range of motion, fatigue, equipment, and how close the set was to your limit can all move the real number. An estimate, not a recommendation to attempt the displayed weight. These percentages are reference loads, not prescribed repetitions or a training program.
Sources
- Brzycki M. Strength testing — predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance. 1993;64(1):88–90. Publication page
- Epley equation: commonly attributed to Boyd Epley (1985). We could not verify an official online copy of the original print source, so no link is given.
Worked example
100 kg × 5 repetitions (the result is the same for female and male users):
- Epley: 100 × (1 + 5 ÷ 30) ≈ 116.7 kg
- Brzycki: 100 × 36 ÷ 32 = 112.5 kg
- 75% of the unrounded Epley estimate: 87.5 kg
- Rounded down to a 2.5 kg increment: 87.5 kg
Example inputs to show the arithmetic, not a recommended load.
Who This Calculator Is For
A good fit
Adult women and men seeking a rough training reference from conventional externally loaded lifts.
Limited usefulness for
- Beginners still learning technique, whose sets may not reflect their capacity.
- Injury rehabilitation, which needs guidance from a qualified professional.
- Assisted movements, where the machine offsets part of the load.
- Bodyweight exercises, which need additional calculations.
- Comparing different machines, which can load the same lift differently.
- Competition attempt selection without coaching context.
One Rep Max Calculator FAQ
What is a one-rep max?
- Your one-rep max (1RM) is the most weight you can lift for one complete repetition of an exercise with controlled technique.
How is it estimated?
- For 2–10 repetitions, the calculator uses the Epley equation: weight × (1 + reps ÷ 30). For one repetition, it shows the weight you entered as a completed single.
Does the formula differ for women and men?
- No. The same Epley and Brzycki equations are used for women and men, and identical weights and repetitions produce identical results.
Why ask Female/Male if the equation is the same?
- The page includes the selection to make its support for women and men explicit. It is not a mathematical input to these equations.
How accurate is the estimate?
- It is a broad reference, not a measurement. Accuracy depends on technique, range of motion, fatigue, equipment, and how close your set was to your limit. Sets with fewer repetitions generally give a more reliable reference than higher-repetition sets.
Why are repetitions limited to 10?
- Predictions become more uncertain as repetitions increase, so the calculator accepts 1–10 repetitions and flags sets of 6–10 as a broader reference.
Should I try the estimated maximum?
- You do not need to. The estimate is a planning reference, not a recommendation to attempt the displayed weight. If you test heavy lifts, use appropriate safety equipment and qualified supervision when needed.
Do I include the bar?
- Yes. Enter the total external weight, including the bar.
How do I enter dumbbell weight?
- For two dumbbells, enter their combined weight. All results will then represent combined weight.
Can I compare different machines?
- Not reliably. Machines can load the same movement differently, so an estimate from one machine may not transfer to another.
What happens when I enter one repetition?
- The calculator shows the weight you entered as a “Completed Single” and bases the reference loads on it. It does not establish that it was your maximum.
Why do Epley and Brzycki differ?
- They are different formulas fitted to repetition data in different ways, so they give different outputs for the same set. The gap between them is not a confidence interval.
Is my information saved?
- No. Everything is calculated in your browser. Your female/male selection, exercise, weight, repetitions, and results are not sent, saved, or included in analytics.
Give Your Next Session a Clearer Strength Reference.
Enter a recent completed set and review your estimated maximum and reference loads.