One rep max, without the spreadsheet
Free 1RM calculator
Punch in a set you actually did. Get the one-rep max you didn't — the PR you can brag about without the inconvenience of attempting it. Plus what to load for everything else.
| % of 1RM | ≈ reps | Weight |
|---|---|---|
| 90% | 4 | 105 kg |
| 85% | 6 | 100 kg |
| 80% | 8 | 92.5 kg |
| 75% | 10 | 87.5 kg |
| 70% | 12 | 82.5 kg |
What a 1RM actually is
Your one-rep max (1RM) is the heaviest weight you can lift for a single rep with passable form. More usefully than party bragging, it's the anchor your whole program hangs off — most strength work is prescribed as a percentage of your 1RM.
Why estimate instead of just testing it
Testing a true max is taxing, occasionally stupid, and you can't do it every week.
So you do the math instead: lift a weight for a few reps, and a formula estimates
the single you'd have grinded out. This uses the Epley formula —
1RM = weight × (1 + reps ÷ 30) — the same one the JeeVeli app uses.
Read the estimate like an adult
It's an estimate. Your sleep, your last meal, and whether anyone's watching all move the real number. The fewer reps you put in, the closer the estimate; a 10-rep set is a wild guess wearing a lab coat. Treat the result as a starting load, not a prophecy — then go find out for real.
Where 1RM lives in JeeVeli
Open any exercise in the app and JeeVeli shows its estimated 1RM, worked out from your best set with the same Epley math you just used here — no typing required. Right below it sits a chart you can flip to 1RM and watch the estimate climb session over session, and it flags a new PR when you set one. Per exercise, updated every time you log. The calculator up there is the one-off; the app is the version that remembers.