one-rep max calculator
Estimate a one-rep max from any weight and reps, with the same three formulas the platform prescribes from. Every result carries the estimated mark, because an estimate is never a measured max.
Whole reps, taken close to failure. Five to eight give the steadiest read.
Most lifts. An Epley-family curve tuned to the platform's logged data, slightly more conservative than the textbook.
Every figure above carries the estimated mark for a reason: a formula reads a set, it does not watch you lift. The platform treats its own numbers the same way, so an estimated max never poses as a measured one.
one curve does not fit every movement.
A bench press and a lat pulldown do not fatigue the same way, so the same set of eight reps implies a different max for each. Trainbase tags every exercise in its 1,100+ movement library with the estimation curve it is measured by, and this calculator carries the same three.
| standard | back and biceps | leg press / extensions | |
|---|---|---|---|
| built for | most barbell and dumbbell lifts | rows, pulldowns, curls | machine leg work |
| shape | Epley-family curve | Epley-family, flatter | power curve, deliberately flat |
| character | the workhorse, tuned slightly conservative of the textbook | the most conservative, because pulls flatter a rep count | keeps a twenty-rep leg press from fabricating a monster max |
| confidence | medium-high, fit to logged training data | the lowest of the three; hold it loosely | high, fit to a clean measured grid |
The same formulas resolve every percentage prescription inside the product. Read more about how that works on the one-rep max page.
the honest answers.
How accurate is an estimated one-rep max?
Accurate enough to program from, not accurate enough to call a record. Low-rep sets taken close to failure estimate tightest; past ten reps the relationship loosens, and past thirty we do not print a number at all. That is why every result here carries the estimated mark.
Why three formulas instead of one?
Because one curve does not hold every movement. Pulling movements overstate a max on the standard curve, and machine leg work overstates it even more, so the platform tags every exercise in its library with the curve it is measured by. This calculator gives you the same three.
What do I do with the percentages table?
That is how strength programs are written: a set prescribed at 75 percent of your one-rep max resolves to a concrete weight. On the platform that resolution happens automatically against each client's own numbers; here you can read it straight off the table.
more free tools
- tdee calculatorMaintenance calories from Mifflin-St Jeor and an honest activity multiplier.
- macro calculatorA calorie target split into protein, fat, and carbs, priced at 4/4/9.
- protein calculatorA daily protein range by goal, never a false-precision decimal.
- body fat calculatorThe US Navy tape-measure estimate, marked as the rough proxy it is.
- calorie deficit calculatorAn intake target and an honest weekly rate; below-BMR plans are refused.
a calculator estimates once. the platform watches what actually happens.
Every number this page gives you is a starting point. Trainbase is where a coach and a client watch the real ones move: every set logged against a program, every reading on one honest scale, every estimate marked as an estimate. When the trend disagrees with the calculator, the trend wins.