ffee
All tools
One Rep Max Calculator
Estimate your one rep max from a set you have already lifted, using the Epley and Brzycki formulas.
Estimated one rep max
Epley: —
Brzycki: —
Percentage table of 1RM
How to use the One Rep Max Calculator
- Enter the weight you lifted and the reps you completed.
- Compare the Epley and Brzycki one rep max estimates.
- Use the percentage table to pick training loads.
Features
- Epley and Brzycki formulas side by side
- Percentage table from 100 down to 60 percent
- Works for any barbell lift
- Runs locally, no uploads
Advertisement
Frequently Asked Questions
Common questions about the free online one rep max calculator.
Your one rep max is the heaviest weight you can lift once with good form for a given exercise
such as the bench press or squat.
Epley and Brzycki both work best between three and eight reps. The tool shows both figures
and averages them in the percentage table.
Epley multiplies the weight by one plus your reps divided by thirty, so five reps at 100
kilograms gives about 117 kilograms.
Brzycki divides thirty six by thirty seven minus the reps, which usually gives a slightly
lower estimate than the Epley formula.
It is usually within a few percent for sets of five or fewer reps, but it drifts as the rep
count rises above ten.
Only with a spotter and sound technique. Estimating from a hard set of three to five reps is
safer and nearly as useful.
It converts your estimated max into training loads, so you can pick a weight for a set of
five or eight without testing your maximum.
It works best for compound barbell lifts. Isolation exercises and high rep sets give
noticeably less reliable estimates.
Retest every four to eight weeks during a strength block, or whenever you clearly beat your
old rep performance at the same weight.
No. The estimate is for general information only and is not medical advice, so train within
your limits and seek coaching.
Last updated: October 10, 2026