One Rep Max Calculator
With weight lifted 185 lbs, reps completed 5, one rep max comes to 212 lbs — estimated one-rep max. It is reached in 12 steps, the last of which is (215.83333 + 208.125 + 217.3045 + 208.125) / 4, and each one is printed on the page with its numbers filled in. The formula is the one published by García-Ramos et al. (2019), Journal of Sports Sciences, not an approximation fitted to it.
Your one-rep max from a set to failure, by all four published formulas at once, with the spread between them and how far they run high.
Formula and sources checked · How we check
Weight lifted 185 lbs, Reps completed 5
212 lbs
Estimated one-rep max for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Epley
185 * (1 + 5 / 30)215.833 lbs- Brzycki
185 * 36 / (37 - 5)208.125 lbs- Lombardi
185 * pow(5, 0.1)217.305 lbs- O'Conner
185 * (1 + 5 / 40)208.125 lbs- Estimated one-rep max
(215.83333 + 208.125 + 217.3045 + 208.125) / 4212.347 lbs- Spread between the four
max(215.83333, 208.125, 217.3045, 208.125) - min(215.83333, 208.125, 217.3045, 208.125)9.18 lbs- Spread as a share of the estimate
9.1795045 / 212.34696 * 1004.323 %- After the measured 3.75% overestimate
212.34696 / 1.0375204.672 lbs- 95% — singles and doubles
212.34696 * 0.95201.73 lbs- 85% — sets of about five
212.34696 * 0.85180.495 lbs- 75% — sets of about ten
212.34696 * 0.75159.26 lbs- 65% — volume work
212.34696 * 0.65138.026 lbs
Worked example
Five reps at 185 lb gives an estimated max of 212 lb, and the four formulas land within 9 lb of each other — 4.3% — which is about as tight as this method gets. Take the measured overestimate off and it is 205 lb.
How to work it out yourself
- 1.Take one set to genuine failure, in the 3-6 rep range, with a spotter or in a rack.
- 2.Enter the load on the bar and the number of clean reps you completed.
- 3.Read the estimate, then look at the spread: a wide spread means the rep count was too high for the method.
- 4.Use the percentage rows to set working loads rather than testing a true max every week.
What the four formulas say for 185 lb, by reps
| Reps completed | Estimated one-rep max | Epley | Brzycki | Lombardi | Spread as a share of the estimate |
|---|---|---|---|---|---|
| 1 | 188 lbs | 191.17 lbs | 185 lbs | 185 lbs | 3.29 % |
| 2 | 195 lbs | 197.33 lbs | 190.29 lbs | 198.28 lbs | 4.1 % |
| 3 | 201 lbs | 203.5 lbs | 195.88 lbs | 206.48 lbs | 5.27 % |
| 4 | 207 lbs | 209.67 lbs | 201.82 lbs | 212.51 lbs | 5.17 % |
| 5 | 212 lbs | 215.83 lbs | 208.13 lbs | 217.3 lbs | 4.32 % |
| 6 | 218 lbs | 222 lbs | 214.84 lbs | 221.3 lbs | 4.25 % |
| 8 | 228 lbs | 234.33 lbs | 229.66 lbs | 227.76 lbs | 5.4 % |
| 10 | 239 lbs | 246.67 lbs | 246.67 lbs | 232.9 lbs | 6.44 % |
| 12 | 251 lbs | 259 lbs | 266.4 lbs | 237.19 lbs | 11.65 % |
| 15 | 269 lbs | 277.5 lbs | 302.73 lbs | 242.54 lbs | 22.35 % |
| 20 | 307 lbs | 308.33 lbs | 391.76 lbs | 249.62 lbs | 46.33 % |
The four sit within about 5% of each other out to ten reps and then come apart: at twenty the spread is 46% — 142 lb across a 307 lb estimate, because Brzycki divides by 37 minus the rep count. That widening is the method losing its meaning, not the formulas disagreeing about a fact.
The formula
- Epley
185 * (1 + 5 / 30) - Brzycki
185 * 36 / (37 - 5) - Lombardi
185 * pow(5, 0.1) - O'Conner
185 * (1 + 5 / 40) - Estimated one-rep max
(215.83333 + 208.125 + 217.3045 + 208.125) / 4 - Spread between the four
max(215.83333, 208.125, 217.3045, 208.125) - min(215.83333, 208.125, 217.3045, 208.125) - Spread as a share of the estimate
9.1795045 / 212.34696 * 100 - After the measured 3.75% overestimate
212.34696 / 1.0375 - 95% — singles and doubles
212.34696 * 0.95 - 85% — sets of about five
212.34696 * 0.85 - 75% — sets of about ten
212.34696 * 0.75 - 65% — volume work
212.34696 * 0.65
Source: García-Ramos et al. (2019), Journal of Sports Sciences — Reliability and validity of different methods of estimating the one-repetition maximum, Dhahbi et al. (2024), Journal of Strength and Conditioning Research — 4-6 RM and 1-RM prediction in free-weight bench press and Smith machine squat
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