One Rep Max Calculator
One Rep Max Calculator
Find your true strength baseline. Enter the weight you lifted and how many reps you completed — we’ll calculate your estimated one rep max instantly.
What is a one rep max?
Your one rep max (1RM) is the maximum amount of weight you can lift for a single rep with proper form. It’s the gold standard for measuring raw strength and is used by powerlifters, athletes, and serious gym-goers to track progress and structure training programs.
Why does it matter?
Knowing your 1RM lets you train with precision. Most strength programs are built around percentages of your 1RM — so instead of guessing what weight to use, you can calculate exactly where to train for your goal:
- 90–100% of 1RM → maximal strength
- 75–85% of 1RM → hypertrophy (muscle growth)
- 60–75% of 1RM → endurance and volume work
How is it calculated?
This calculator uses three of the most respected formulas in strength science — Epley, Brzycki, and Lander — and averages the results for the most accurate estimate. Results are most reliable when calculated from sets of 10 reps or fewer.
Safety first — Never attempt a true 1RM without a spotter and proper warm-up. Use this calculator as an estimate and build toward your max progressively over time.
Units
Training zones
Formula breakdown
| Formula | Estimated 1RM |
|---|---|
| Epley | — |
| Brzycki | — |
| Lander | — |
Your result is the average of all three formulas · Most accurate for sets of 1–10 reps
