1RM calculator
Calculate your One Rep Max (1RM) using the Epley formula. Determine optimal training weights for 1–12 reps from your submaximal weight.
Note: This calculation is only a rough estimate and does not replace individual advice.
Frequently Asked Questions
7Methodology
How does the calculator work?
Methodology
How does the calculator work?
- Enter the weight you lifted
- Enter the number of clean repetitions
- Read your estimated 1RM
- Use the table for optimal training weights
The calculator uses the Epley formula: 1RM = Weight × (1 + Reps / 30).
1What is the 1RM (One Rep Max)?
The 1RM is the maximum weight you can lift exactly once with proper form for a given exercise. It serves as a reference value for training planning.
2How accurate is the calculation?
The Epley formula provides good estimates for 1-10 repetitions. With higher rep counts, the estimate becomes less accurate. Actual max strength can vary individually.
3Why should I not test my 1RM directly?
Max tests carry an increased risk of injury and require a lot of experience. Calculating from submaximal weights is safer and sufficiently accurate for training planning.
4How do I use the table for my training?
The table shows you the optimal weight for different rep ranges. For strength building, train with 1-5 reps; for hypertrophy, train with 6-12 reps.
5Does the 1RM apply to all exercises?
The 1RM is exercise-specific. Your bench press 1RM differs from your squat 1RM. Calculate it separately for each exercise.
6How is the data calculated?
The calculator estimates your one-rep max (1RM) using the widely used Epley formula. From the lifted weight and the number of proper repetitions, it calculates your possible maximum weight for one repetition.
1RM = weight × (1 + reps / 30)
The formula provides estimates; other equations such as Brzycki or Mayhew also exist and may yield slightly different results depending on the exercise.
7What studies is the calculation based on?
- LeSuer et al. (1997)
Key point: Compared several 1RM prediction formulas and found Epley and Brzycki to provide good estimates in untrained individuals.
Source: Journal of Strength and Conditioning Research - Mayhew et al. (1992)
Key point: Developed and validated equations to predict 1RM from submaximal repetitions.
Source: PubMed
The actual 1RM can be influenced by technique, fatigue or daily condition. Test heavy weights only with proper safety and use the calculated values as a guideline.