100w ÷ (48.8 + 53.8 × e^(−0.075r)) — A sleeper exponential formula that gets interesting when the familiar linear estimates stop agreeing with your higher-rep set.
Strength levels for a 200lb male, age 30 lifting 253lb in each lift type · enter your details.
Wathan algorithm
| Reps | Weight (lb) |
|---|---|
| 1RM | 253lb |
| 2RM | 246lb |
| 3RM | 239lb |
| 4RM | 232lb |
| 5RM(current) | 225lb |
| 6RM | 218lb |
| 7RM | 211lb |
| 8RM | 204lb |
| 9RM | 197lb |
| 10RM | 190lb |
| 20RM | 119lb |
Based on 253lb estimated max
| Intensity | Weight (lb) |
|---|---|
| 100% | 253lb |
| 95% | 240lb |
| 90% | 228lb |
| 85% | 215lb |
| 80% | 202lb |
| 75% | 190lb |
| 70% | 177lb |
| 65% | 164lb |
| 60% | 152lb |
| 55% | 139lb |
| 50% | 127lb |
Input: Input set: 225 lb x 8 reps
Calculation: Formula: 100 x 225 / (48.8 + 53.8 x e^(-0.075 x 8)) = 281.7
Result: Estimated 1RM: 282 lb
Wathan is another curved formula, so it is useful when you want a research-backed estimate that does not stay perfectly linear as reps increase.
Wathan is a good formula to check when you want something less obvious than Epley vs Brzycki. Its curved model can expose how much your estimate depends on the formula once reps start creeping upward.
Both formulas use a curve rather than a simple linear progression, so they become especially interesting once reps climb. Comparing Wathan and Mayhew helps you see whether the higher-rep estimate is consistently rising or only one formula is pushing it upward.
Not automatically, but Wathan gives you a different lens on higher-rep sets. If Epley feels too simplistic once fatigue becomes a factor, Wathan is worth checking as a second opinion rather than treating any one equation as final truth.
