Estimate your true one-rep max from any set of 2-10 reps — no need to actually attempt a risky single-rep max out.
| % of 1RM | Weight | Typical Use |
|---|---|---|
| 95% | 0 lb | Max strength, 1-2 reps |
| 85% | 0 lb | Strength, 3-5 reps |
| 75% | 0 lb | Strength-hypertrophy, 6-8 reps |
| 65% | 0 lb | Hypertrophy, 10-12 reps |
| 50% | 0 lb | Technique / warm-up, 15+ reps |
Epley and Brzycki are the two most widely used 1RM estimation formulas, and they're built on slightly different assumptions about how strength declines as reps increase. They usually land within a few pounds of each other at moderate rep ranges (5-8 reps) and diverge more at higher rep counts. Showing both gives you a realistic range rather than a single number presented as more precise than it actually is.
A true 1-rep max attempt is high-risk for injury, especially without a spotter, and it's taxing on your nervous system for days afterward. Most lifters are better served estimating 1RM from a heavier set like this calculator does, and saving actual max-out attempts for competition or testing days a few times a year at most. Once you know your 1RM, see how it stacks up pound-for-pound against lifters of any bodyweight with our DOTS Calculator or Wilks Calculator.
Neither is universally "more accurate" — Brzycki tends to estimate slightly lower at higher rep counts, while Epley tends to estimate slightly higher. Studies comparing both against actual tested 1RMs show mixed results depending on the lift and the lifter's training background.
It works best for compound barbell lifts (squat, bench, deadlift, overhead press) where strength is the primary limiting factor. It's less reliable for exercises where stabilizer muscles or technique fatigue faster than the prime mover, like single-arm or balance-dependent movements.
If your reps-to-failure dropped (e.g., you used to get 10 reps at a weight and now only get 7), the formula will show a lower estimate even if your actual max went up, because it's estimating from rep endurance, not measuring max strength directly. Test with a consistent rep range over time for the most meaningful trend.