One-rep max (1RM) calculator
You do not need to test a true max: enter the weight lifted and the number of clean reps, and the tool estimates your 1RM.
Your results will appear here.
How it works
- Do one demanding set with clean technique, between 2 and 12 reps.
- Epley: 1RM = weight × (1 + reps / 30). Brzycki: 1RM = weight × 36 / (37 − reps).
- The tool shows the average of both formulas, most accurate between 3 and 8 reps.
- The table converts this 1RM into working weights: roughly 85% for 5 reps, 75% for 10.
Frequently asked questions
Is an estimated 1RM reliable?
It is most reliable with 3 to 8 reps. Beyond 12, the error grows a lot, and fatigue or technique distort the result.
Should I test my true max?
No, especially as a beginner: a max test carries risk. The estimate is enough to calibrate your training weights.
Which percentage should I train at?
Usually 65 to 80% of 1RM for 6 to 12 reps (muscle growth), 80 to 90% for 2 to 5 reps (strength).
How often should I recalculate?
Every 4 to 8 weeks, or after a progression cycle, to adjust your weights.
Put it to work with a program
More tools : Calories and macros · Running pace and race times