Epley vs Brzycki vs Lombardi: Which 1RM Formula Should You Use?
The three rep-based formulas behind our one rep max calculator, compared rep by rep, so you can see where they agree, where they split, and what that means for your training numbers.
Quick answer
From 2 to 10 reps, Epley, Brzycki and Lombardi agree within about 3–6%, so any of them (or their average) is a reasonable 1RM estimate. Past 10 reps they split fast — an 11.5% spread at 12 reps — and that disagreement is the real warning: estimates from high-rep sets are rough. Brzycki gives the lowest estimate up to 7 reps; Lombardi gives the lowest from 8 reps on.
Result
| Epley | |
| Brzycki | |
| Lombardi | |
| Spread (highest − lowest) |
The three formulas
Brzycki: 1RM = w × 36 ÷ (37 − r)
Lombardi: 1RM = w × r0.10
w = weight lifted, r = reps completed
These are the exact equations in TrainMath's calculator code. Our calculators accept 1–12 reps; a higher rep count is treated as 12, because the formulas were built for low-to-moderate rep sets and disagree more the further you go.
Rep-by-rep comparison (estimated 1RM for 100 lifted)
| Reps | Epley | Brzycki | Lombardi | Average | Spread |
|---|---|---|---|---|---|
| 1 | 103.3 | 100.0 | 100.0 | 101.1 | 3.3% |
| 2 | 106.7 | 102.9 | 107.2 | 105.6 | 4.1% |
| 3 | 110.0 | 105.9 | 111.6 | 109.2 | 5.2% |
| 4 | 113.3 | 109.1 | 114.9 | 112.4 | 5.1% |
| 5 | 116.7 | 112.5 | 117.5 | 115.5 | 4.3% |
| 6 | 120.0 | 116.1 | 119.6 | 118.6 | 3.3% |
| 7 | 123.3 | 120.0 | 121.5 | 121.6 | 2.7% |
| 8 | 126.7 | 124.1 | 123.1 | 124.6 | 2.8% |
| 9 | 130.0 | 128.6 | 124.6 | 127.7 | 4.2% |
| 10 | 133.3 | 133.3 | 125.9 | 130.9 | 5.7% |
| 11 | 136.7 | 138.5 | 127.1 | 134.1 | 8.5% |
| 12 | 140.0 | 144.0 | 128.2 | 137.4 | 11.5% |
What the table shows
- Epley and Brzycki cross at exactly 10 reps (both 133.3). Below 10, Epley is higher; above 10, Brzycki climbs faster and becomes the most aggressive.
- Lombardi flattens out. Because it uses reps to the 0.10 power, each extra rep adds less. It is the highest estimate at 2–5 reps but the lowest from 8 reps on.
- Agreement is best at 6–8 reps (2.7–3.3% spread). If you want one set to estimate from, a hard set of about 6–8 is where the three formulas line up most closely.
- Single reps: Epley returns 103.3% of the load for 1 rep, the other two return 100%. If you truly lifted a single, use that number, not a formula.
Worked examples
| Set | Epley | Brzycki | Lombardi | Average |
|---|---|---|---|---|
| 225 lb × 5 | 262.5 | 253.1 | 264.3 | 260.0 |
| 315 lb × 3 | 346.5 | 333.5 | 351.6 | 343.9 |
| 100 kg × 8 | 126.7 | 124.1 | 123.1 | 124.6 |
| 60 kg × 10 | 80.0 | 80.0 | 75.5 | 78.5 |
| 135 lb × 12 | 189.0 | 194.4 | 173.1 | 185.5 |
Check by hand: 225 lb × 5
- Epley: 225 × (1 + 5 ÷ 30) = 225 × 1.1667 = 262.5 lb
- Brzycki: 225 × 36 ÷ 32 = 253.1 lb
- Lombardi: 225 × 50.10 = 225 × 1.1746 = 264.3 lb
- Average: (262.5 + 253.1 + 264.3) ÷ 3 = 260.0 lb
Estimated 1RM ≈ 260 lb, with an 11 lb (about 4%) range between formulas.
Notice the 135 lb × 12 row: the formulas disagree by more than 21 lb. A high-rep set tells you about muscular endurance as much as maximal strength, so treat the estimate as a starting point only.
Which one should you use?
- For programming percentages, the three-formula average is a practical middle ground; that is what our 1RM percentage chart and lift calculators display.
- If you want a cautious number for a first attempt at a heavy single, use the lowest of the three estimates.
- Be consistent. Track the same formula from the same kind of set over time; a change in formula can look like a change in strength.
Lift-specific versions: bench press 1RM, squat 1RM and deadlift 1RM.
Limitations
- All three are generic equations; they do not know your training age, lift technique, or how close to failure the set was.
- Reps above 12 are clamped to 12 in our calculators, so very high-rep sets are not extrapolated further.
- The table describes how the formulas behave, not how accurate they are for you. Only a properly supervised max test measures a true 1RM.
FAQ
Which 1RM formula is most accurate?
No single formula wins for every lifter. From 2 to 10 reps, Epley, Brzycki and Lombardi stay within about 3–6% of each other, so the choice matters less than using a recent, clean set. Above 10 reps they diverge quickly, which is a sign that any estimate is less reliable there.
Why do Epley and Brzycki give the same answer at 10 reps?
Epley gives weight × (1 + 10/30) = 1.333 × weight and Brzycki gives weight × 36/27 = 1.333 × weight. The two curves cross at exactly 10 reps; below 10 Epley is higher, above 10 Brzycki is higher.
Why does Epley give more than the weight lifted for a 1-rep set?
Epley's equation adds 1/30 of the weight for every rep, including the first, so 1 rep returns 103.3% of the load. Brzycki and Lombardi return exactly the weight lifted at 1 rep. If you actually lifted a single, that weight is your tested 1RM.
What 1RM does 225 lb for 5 reps give?
Epley 262.5 lb, Brzycki 253.1 lb, Lombardi 264.3 lb; the average of the three is 260.0 lb. That is an 11 lb spread, about 4% of the average.
Last updated: October 15, 2026.