How it works
Enter the weight and how many reps you did. We use three well-known formulas — Epley, Brzycki and Lombardi — and show their average. Sets of 3–8 reps give the most accurate result.
How to use the percentage table
- 85–100%: 1–5 reps, maximum strength.
- 70–85%: 6–12 reps, muscle growth and strength.
- 50–70%: 12+ reps, technique, warm-up, endurance.
Most strength programs are written in percentages of 1RM. Save your max to My progress and update it every 4–8 weeks.
Safety
Test a true one-rep max only with good technique, a proper warm-up and a spotter or safety bars. An estimate from a set of 3–5 reps is enough for most people.
Questions and answers
How accurate is a 1RM calculator?
With 3–8 reps the estimate is usually within 3–5% of a real max. With more reps it becomes less accurate.
Which formula is best?
No single formula is best for everyone. That is why we show the average of three formulas — it smooths out their differences.
How often should I test my max?
Every 4–8 weeks is enough. You can estimate it from regular heavy sets without a special test day.
How it is calculated: sources
- Epley B. Poundage chart. Boyd Epley Workout. 1985.
- Brzycki M. Strength testing — predicting a one-rep max from reps-to-fatigue. JOPERD. 1993;64(1):88–90.
- LeSuer DA et al. The accuracy of prediction equations for estimating 1-RM performance. J Strength Cond Res. 1997;11(4):211–213.
Gymvert gives general information for healthy adults. It is not medical advice. If you have a health condition, are pregnant, or are unsure, talk to a doctor before changing your training or diet.