3 reps
- Input
- 100 kg x 3
- Expected output
- Epley 110,0 kg | Brzycki 105,9 kg
At low reps Epley gives about 4 kg more than Brzycki.
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Epley vs Brzycki formula
Epley and Brzycki are the two most cited 1RM formulas, and between 2 and 10 reps they differ by only a few percent. Below is where they match, where they split and why that matters when choosing.
At low reps Epley gives about 4 kg more than Brzycki.
1 + 10/30 = 1.3333 and 36/27 = 1.3333: the exact crossover point.
Above 10 reps Brzycki shoots up (211.8 kg at 20 reps), a sign the estimate is no longer reliable.
It is the heaviest load you can lift for a single full repetition with correct technique in a given exercise. It is a reference for dosing training in percentages, not a goal and not something you are obliged to test.
It depends on the lift and the group studied. Neither is universally better: at 2 to 8 reps the two are close, and above 10 neither is reliable. That is why the average and range are more honest than one value.
Because it divides by (37 - reps): at 37 the denominator is zero and above it turns negative. Epley, being linear, has no such limit, but that does not make it more accurate in long sets.
Yes, and it is recommended. The Estimate 1RM tab shows both side by side with five other formulas, the average and the range, and the per-rep comparison table shows where they drift apart.
| Formula | 1RM (kg) |
|---|---|
| Epley | 116.7 |
| Brzycki | 112.5 |
| Lander | 113.7 |
| Lombardi | 117.5 |
| Mayhew | 119 |
| O'Conner | 112.5 |
| Wathan | 116.6 |
Each formula is a regression fitted to specific groups and lifts, so the values differ. Averaging the seven reduces the bias of any one, but does not remove the error.
The fraction of 1RM each formula assigns to each rep count. They agree closely at low reps and drift apart as reps grow.
| Reps | Epley | Brzycki | Lander | Lombardi | Mayhew | O'Conner | Wathan |
|---|---|---|---|---|---|---|---|
| 1 | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| 2 | 93.8% | 97.2% | 96% | 93.3% | 89.7% | 95.2% | 95.1% |
| 3 | 90.9% | 94.4% | 93.3% | 89.6% | 87.7% | 93% | 91.8% |
| 4 | 88.2% | 91.7% | 90.6% | 87.1% | 85.8% | 90.9% | 88.7% |
| 5 | 85.7% | 88.9% | 87.9% | 85.1% | 84% | 88.9% | 85.8% |
| 6 | 83.3% | 86.1% | 85.3% | 83.6% | 82.3% | 87% | 83.1% |
| 8 | 78.9% | 80.6% | 79.9% | 81.2% | 79.2% | 83.3% | 78.3% |
| 10 | 75% | 75% | 74.6% | 79.4% | 76.4% | 80% | 74.2% |
| 12 | 71.4% | 69.4% | 69.2% | 78% | 73.9% | 76.9% | 70.7% |
| 15 | 66.7% | 61.1% | 61.2% | 76.3% | 70.6% | 72.7% | 66.3% |
This is a mathematical estimate, not a real test or a training prescription. Only attempt a true 1RM with good technique, a warm-up, safety pins or a spotter, ideally under professional supervision. If you have an injury or a health condition, talk to a professional first.