One-rep max calculator
Enter a weight and the number of clean reps you got with it. The calculator estimates your one-rep max two ways, and gives you the percentage table you actually need for programming.
Use a set taken close to failure, with eight reps or fewer. Estimates from high-rep sets are unreliable — a set of twenty tells you far more about your work capacity than about your maximum.
Two formulas are shown because they disagree, and knowing by how much is more useful than a single confident-looking number. Epley tends to read higher at high reps; Brzycki tends to read lower.
| % of 1RM | Weight | Typically used for |
|---|
What the number means
The formulas
Epley: 1RM = weight × (1 + reps ÷ 30)
Brzycki: 1RM = weight × 36 ÷ (37 − reps)
Both are decades-old regression estimates fitted to populations, not laws. They agree closely at low reps and drift apart as reps climb, which is why this calculator shows you both and averages them rather than picking a winner.
Why you probably should not test a true 1RM
A 3RM is safer, less fatiguing, more repeatable, and accurate enough for the only thing the number is actually used for — setting the weights on your working sets. Train Smart accepts a 3RM in the same field as a 1RM and converts it for you, precisely so nobody has to max out alone in a commercial gym.
What the number is for
Percentages of a max are how strength programs assign load: 5 × 3 at 80%, 4 × 5 at 78%, and so on. That is useful, and it is also the part almost nobody keeps up with, because it means recalculating every weight every time you get stronger.
That recalculation is what Train Smart's prescribed weights do automatically: every working set is given a weight in kilos, derived from your most recent top set on that exact movement and the week you are in within the four-week block, and rounded to what the bar or the dumbbell rack actually goes up in.
Common questions
How accurate is a 1RM calculator?
Should I use Epley or Brzycki?
Can I use this to set my training weights?
Or let the app do it every week
Train Smart runs this calculation continuously — recalculating your working weights, your conditioning paces and your load every session, without you opening a calculator.
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