One Rep Max (1RM) Calculator
Estimate your one rep max using the Epley formula.
Enter the weight lifted and number of reps to find your estimated 1RM and training percentages.
Estimated One Rep Max
One Rep Max (1RM) is the maximum weight you can lift for a single repetition. It is commonly estimated from a submaximal lift.
Epley Formula:
1RM = Weight × (1 + Reps / 30)
This formula is most accurate for rep ranges of 2–10. For single reps, the weight itself is your 1RM.
Training percentage guidelines:
- 100% 1RM: Max effort (1 rep)
- 90% 1RM: Very heavy (2–3 reps)
- 80% 1RM: Heavy (4–6 reps)
- 70% 1RM: Moderate (8–12 reps)
- 60% 1RM: Light (15–20 reps)
Other popular 1RM formulas:
- Brzycki:
1RM = Weight × (36 / (37 - Reps)) - Lombardi:
1RM = Weight × Reps^0.10
The Epley formula is the most widely used and generally the most accurate for moderate rep ranges.