Epley Formula
One of the most widely used one rep max formulas in strength training software and coaching programs.
The equation
1RM = weight × (1 + reps ÷ 30)
Worked example
Say you bench press 100 kg for 5 reps. Plugging into the formula:
1RM = 100 × 1.1667
1RM ≈ 116.7 kg
When to use the Epley formula
Epley works best for sets of 1-10 reps performed close to failure. It's simple to calculate by hand, which is why it became a default in so many gym apps and whiteboards. Because it assumes a straight-line relationship between reps and intensity, it becomes less reliable for very high-rep sets — for those, a rep-max table or a formula tuned for higher reps (like Lombardi) can be more appropriate.
Try it yourself
Enter your lift
Your estimated one rep max
Bench Press · estimated 1RM
117.5 kg
Raw estimate: 116.7 kg · 257.2 lb
Epley
116.7 kg
Brzycki
112.5 kg
Lombardi
117.5 kg
Training percentages
| % | Weight | Reps |
|---|---|---|
| 100% | 116.7 kg | 1 rep |
| 95% | 110.8 kg | 1-2 reps |
| 90% | 105.0 kg | 2-3 reps |
| 85% | 99.2 kg | 3-5 reps |
| 80% | 93.3 kg | 4-6 reps |
| 75% | 87.5 kg | 6-8 reps |
| 70% | 81.7 kg | 8-10 reps |
| 65% | 75.8 kg | 10-12 reps |
| 60% | 70.0 kg | 12-15 reps |
| 50% | 58.3 kg | 15-20 reps |
| 40% | 46.7 kg | 20+ reps |
Estimated weight for 1–12 reps
1 rep
116.7 kg
2 reps
109.4 kg
3 reps
106.1 kg
4 reps
102.9 kg
5 reps
100.0 kg
6 reps
97.2 kg
7 reps
94.6 kg
8 reps
92.1 kg
9 reps
89.7 kg
10 reps
87.5 kg
11 reps
85.4 kg
12 reps
83.3 kg
Epley formula FAQ
Who created the Epley formula?+
Strength coach Boyd Epley popularized this formula in the 1980s. It remains one of the most widely used 1RM estimation formulas in strength and conditioning software today.
When is Epley less accurate?+
Epley tends to overestimate 1RM for sets above roughly 10-12 reps, since the linear relationship it assumes between reps and load breaks down at higher rep ranges. Use a lower-rep set (1-8 reps) for best accuracy.
How does Epley compare to Brzycki?+
Epley is slightly more conservative at low reps and slightly higher at high reps compared to Brzycki. Neither is universally 'more accurate' — individual variation matters more than the formula choice. See our full comparison.
Compare it directly with the Brzycki formula or see a full formula comparison.