Tools Strength
1RM calculator
Enter one recent working set and get your estimated one-rep max, plus the training loads at every percentage from 95 down to 70. Works in pounds or kilograms. Nothing leaves your browser.
An estimated 1RM (e1RM) takes a set you actually did, the weight and the reps, and projects the single heaviest rep you could manage. It is the cleanest way to compare lifts over time and to set training loads as percentages, without grinding an actual max. This calculator uses the Epley formula, the same estimate the Anneal app runs on every set you log.
Estimate your 1RM
How to read the table
The percent-of-1RM table turns your estimate into training weights. Each row shows the load at that percentage and the approximate reps it allows, derived from the same Epley relationship so the numbers stay consistent with your e1RM. The 70 percent row sits just past the reliable range, so its rep figure is flagged as approximate. Reps at a given percent also vary by exercise and by lifter, so use these as a starting point and adjust by feel.
Pairing this with reps in reserve is often more practical than chasing exact percentages. See the RIR-to-load calculator to turn a target effort into a weight, and RIR explained for the scale.
Common questions
How accurate is an estimated 1RM?
This calculator uses the Epley formula, which is reliable from 1 to about 10 reps and starts to over-predict past 12. The fewer reps in the set you enter, the closer the estimate. A heavy triple or single gives a tighter number than a set of 10. Above 12 reps the estimate is not a trustworthy strength number, so the calculator asks for a set in the 1 to 12 rep range.
How do I use percentages of 1RM?
Percentages translate your max into training loads. Heavy strength work tends to live at 85 percent and up, hypertrophy work in the 65 to 80 percent range, and lighter technique or recovery work below that. The table gives the load at each percent and the rough reps it corresponds to, so you can pick a weight for the effort you want.
Should I test a true 1RM instead?
For most lifters an estimate from a recent hard set is enough to program training, and it carries far less fatigue and injury risk than a true max attempt. Testing a real 1RM has its place in peaking blocks or competition prep, but you do not need to grind a max every time you want a percentage to train off.