About one-rep max (1RM)
Your one-rep max (1RM) is the most weight you can lift for a single repetition. Rather than testing it directly, this calculator estimates it from a weight you lifted for several reps, using the Epley and Brzycki formulas, and gives a training-percentage table so you can plan your sets. It runs in your browser.
How One Rep Max works
How to estimate your 1RM
- Enter the weight you lifted and how many clean reps you did.
- The estimated 1RM appears, plus the Epley and Brzycki values.
- Use the percentage table to plan training loads.
Epley and Brzycki
Both formulas estimate 1RM from sub-maximal sets. The tool averages them for a balanced estimate. Sets of fewer than about 10 reps give the most accurate result.
Training with percentages
Most programmes prescribe loads as a percentage of 1RM — for example 5 reps at ~85%. The table converts your estimated max into weights for each percentage.
Common uses
- Estimate your one-rep max safely
- Plan training loads by percentage
- Track strength progress
- Set working weights for a programme
- Compare lifts without maxing out
- Programme sets and reps
- Estimate maxes for squat, bench and deadlift
- Get a strength reference table
Frequently asked questions
How do I calculate my one-rep max?
Enter a weight and the reps you did; the tool estimates your 1RM with the Epley and Brzycki formulas.
Which formula is more accurate?
They are similar; the tool averages them. Use sets under ~10 reps for the best accuracy.
Do I have to actually lift my max?
No — that is the point: it estimates your max from a lighter, safer set.
What is the percentage table for?
To set training loads — e.g. 5 reps at about 85% of your 1RM.
Does it work in pounds and kilograms?
Yes — choose your unit.
How many reps should I use?
Fewer than about 10 gives the most reliable estimate.
Is my data uploaded?
No — it calculates in your browser.
Is it free?
Yes — completely free with no sign-up.