One rep max calculator
Calculator
The calculator needs JavaScript. The tables below give the same numbers for common cases.
How it is worked out
- Epley: weight × (1 + reps ÷ 30) = 116.7.
- Brzycki: weight × 36 ÷ (37 − reps) = 112.5.
- Lombardi: weight × reps^0.10 = 117.5.
- These estimates are most reliable at 10 or fewer reps and are not a substitute for a coach; test a true max only with a spotter.
| Inputs | Answer |
|---|---|
| Weight lifted: 100; Repetitions: 5 | Estimated one-rep max: about 115.5 (Epley 116.7, Brzycki 112.5, Lombardi 117.5). |
| Weight lifted: 60; Repetitions: 10 | Estimated one-rep max: about 78.5 (Epley 80, Brzycki 80, Lombardi 75.5). |
| Weight lifted: 140; Repetitions: 3 | Estimated one-rep max: about 152.8 (Epley 154, Brzycki 148.2, Lombardi 156.3). |
How to use it
Your one-rep max (1RM) is the most weight you can lift once. Testing it is risky, so it is usually estimated from a set of 2 to 12 reps. The Epley formula is weight × (1 + reps ÷ 30), Brzycki is weight × 36 ÷ (37 − reps) and Lombardi is weight × reps^0.10. The calculator shows all three and their average.
The table also gives 60 to 90% of the average, the working weights commonly used in training programs. Estimates are best for 10 or fewer reps and for people who know the exercise. This is general information and an estimate, not medical advice; talk to a healthcare professional about your own situation.
Frequently asked questions
How do I estimate my 1RM?
Lift a weight for several reps to near failure and apply a formula such as Epley.
Which formula is most accurate?
They differ a little; using the average smooths it out.
Is it safe to test a true 1RM?
Only with good technique, warm-up and a spotter.
Method: standard arithmetic shown step by step; no outside data is used. Checked 2026-11-12.
About · How we verify this · Editorial policy · Corrections
General information only. Results are plain arithmetic on the numbers you enter; check anything important (money, health, school work) against your own records or the official source.