100w ÷ (52.2 + 41.9 × e^(−0.055r)) — The formula to check when your higher-rep set feels stronger than Epley or Brzycki are willing to admit.
Strength levels for a 200lb male, age 30 lifting 268lb in each lift type · enter your details.
Mayhew algorithm
| Reps | Weight (lb) |
|---|---|
| 1RM | 268lb |
| 2RM | 240lb |
| 3RM | 235lb |
| 4RM | 230lb |
| 5RM(current) | 225lb |
| 6RM | 221lb |
| 7RM | 216lb |
| 8RM | 212lb |
| 9RM | 208lb |
| 10RM | 205lb |
| 20RM | 177lb |
Based on 268lb estimated max
| Intensity | Weight (lb) |
|---|---|
| 100% | 268lb |
| 95% | 255lb |
| 90% | 241lb |
| 85% | 228lb |
| 80% | 214lb |
| 75% | 201lb |
| 70% | 188lb |
| 65% | 174lb |
| 60% | 161lb |
| 55% | 147lb |
| 50% | 134lb |
Input: Input set: 225 lb x 8 reps
Calculation: Formula: 100 x 225 / (52.2 + 41.9 x e^(-0.055 x 8)) = 284.1
Result: Estimated 1RM: 284 lb
Mayhew rises faster once reps climb, so it is useful when you want to compare a higher-rep estimate against simpler linear formulas.
Mayhew is the formula people reach for when a 6-10 rep set feels stronger than a strict linear equation admits. Run it beside Epley and Brzycki to see whether the higher number looks inflated or finally believable.
Mayhew uses an exponential curve, so it tends to climb faster once reps increase. That can make it feel more generous, but it is also why lifters like to check it when a solid higher-rep set seems undervalued by stricter formulas.
Mayhew is often more interesting once you move past the classic low-rep strength range. It is not automatically more accurate, but it gives you a useful counterpoint when Epley or Brzycki start looking too conservative for a strong 6-10 rep effort.
