Hip Thrust 1RM from 12 Reps — Epley and Brzycki Estimate
If you can hip thrust 140 kg for 12 reps, your estimated one-rep max is 198.8 kg — the average of the Epley estimate (196.0 kg) and the Brzycki estimate (201.6 kg). That is the headline number, and the rest of this page shows exactly how it was calculated, what loads to train with at every percentage of it, and how far you should trust it.
The Hip Thrust works the glutes, hamstrings, and it is a barbell lift. The worked example below uses a 12-rep set with 140 kg as the load — that is an assumption for illustration, not a prescription for you. Put your own weight and reps into the One Rep Max Calculator and the same two formulas will estimate your own max in seconds. The search term "1rm calculator" is searched an estimated 60,500 times a month (Semrush third-party estimate), which is why so many lifters look for this number — but the number is only useful if you know how it was worked out and what its limits are.
An estimated one-rep max matters because almost every serious strength programme is written in percentages of it. "Five sets of five at 80%" only means something if you know what 100% is, and testing a true one-rep max is risky, fatiguing and unnecessary for most lifters. A submaximal set of 12 reps gives you the number without the risk — provided you understand the limits of the formulas, which this page sets out honestly.
How to perform the hip thrust
Sit on the floor with your upper back against a bench, roll the bar over your hips with a pad, and drive through your heels until your hips are fully extended and your torso is level. Pause briefly at the top and squeeze the glutes, then lower under control. Keep your chin tucked and your ribs down so the lower back does not arch.
That technique standard matters for estimation as much as for safety. The formulas assume the set was taken close to failure with good, repeatable form. A set of 12 reps with two more reps left in the tank will underestimate your max, because the formulas assume those 12 reps were hard. If you stopped well short of failure, treat the estimate as a floor, not a ceiling. And if your technique broke down on the last rep, the set does not count for estimation purposes at all — re-test with a weight you can control for the full range.
Common mistakes on the hip thrust include arching the lower back instead of extending the hips, rushing the lowering phase, placing the feet too far forward or too close, and using a range that the glutes cannot control. Each of these changes the number the formulas produce, so compare estimates only between sets done the same way — same depth, same tempo, same standard. A stricter set that gives a lower estimate is more useful than a sloppy set that gives a higher one.
Use the one-rep-max calculator for your own numbers
The worked example on this page uses 140 kg for 12 reps. Your numbers will be different, and the calculator does the same maths with them. Use the One Rep Max Calculator for this lift, or the general One Rep Max Calculator for any lift, and you will get the Epley estimate, the Brzycki estimate, their average, and the full training-percentage table for your own max.
For comparison, here are related one-rep-max pages — the same two formulas applied to different lifts and rep counts:
- Hip Thrust 1RM from 3 Reps — Epley and Brzycki Estimate
- Hip Thrust 1RM from 5 Reps — Epley and Brzycki Estimate
- Hip Thrust 1RM from 6 Reps — Epley and Brzycki Estimate
The formulas, shown and cited
Two published formulas estimate a one-rep max from a submaximal set. Both are shown here with their sources, and both are worked through with this page's numbers.
Epley (Epley 1985): 1RM = weight × (1 + reps ÷ 30)
Brzycki (Brzycki 1993): 1RM = weight × 36 ÷ (37 − reps)
Worked through for 140 kg × 12 reps on the hip thrust:
- Epley: 140 × (1 + 12 ÷ 30) = 140 × 1.4 = 196.0 kg
- Brzycki: 140 × 36 ÷ (37 − 12) = 140 × 36 ÷ 25 = 201.6 kg
- Average of the two: (196.0 + 201.6) ÷ 2 = 198.8 kg (438 lb)
The two formulas agree to within 5.6 kg on this set. That agreement is itself useful information: when Epley and Brzycki land close together, the estimate is more trustworthy than when they diverge. Twelve reps is just beyond the range where Epley and Brzycki are at their best. The formulas were fitted mainly to sets of ten reps or fewer, so a 12-rep estimate carries a wider error band — treat the average as the middle of a range of several kilograms either way, and prefer a heavier, lower-rep set when you next re-test.
Neither formula is magic. Both were fitted to real lifting data, and both assume the set was taken close to failure with good technique. The gap between them grows as the rep count rises, which is why a 12-rep estimate should be read with the caution described in the limits section below. If you want to see how sensitive the estimate is to the load, the table below runs the same two formulas at three nearby loads for the same 12 reps.
| Load × 12 reps | Epley 1RM | Brzycki 1RM | Average 1RM |
|---|---|---|---|
| 130 kg × 12 reps | 182.0 kg | 187.2 kg | 184.6 kg |
| 140 kg × 12 reps | 196.0 kg | 201.6 kg | 198.8 kg |
| 150 kg × 12 reps | 210.0 kg | 216.0 kg | 213.0 kg |
Read the table across, not down: a 10 kg change in the load you lift for 12 reps moves the estimated max by roughly the same amount, so small, honest improvements in the weight you can lift for 12 reps are real progress, even when the estimated max moves by only a few kilograms.
Training percentages for a 198.8 kg hip thrust max
Most programmes prescribe loads as a percentage of your one-rep max. The table below gives the load for every percentage from 50% to 100% of the 198.8 kg estimate, so you can read your working weights straight off it without doing the multiplication in your head between sets.
| % of 1RM | Load (kg) | Load (lb) |
|---|---|---|
| 50% | 99.4 kg | 219 lb |
| 55% | 109.3 kg | 241 lb |
| 60% | 119.3 kg | 263 lb |
| 65% | 129.2 kg | 285 lb |
| 70% | 139.2 kg | 307 lb |
| 75% | 149.1 kg | 329 lb |
| 80% | 159.0 kg | 351 lb |
| 85% | 169.0 kg | 373 lb |
| 90% | 178.9 kg | 394 lb |
| 95% | 188.9 kg | 416 lb |
| 100% | 198.8 kg | 438 lb |
How those percentages are used in practice depends on the goal. Strength work lives at 85–95% of 1RM for sets of 1–5 reps, with long rests of three to five minutes. Hypertrophy work lives at 65–85% for sets of 6–12 reps, with rests of 60–120 seconds. Muscular endurance work lives at 50–65% for sets of 15 or more reps, with short rests. The same max produces all three training zones; what changes is the percentage and the rep count, not the lift.
A practical example: if your programme calls for five sets of five at 80% on the hip thrust, that is 159.0 kg for five reps, five times, with three minutes of rest between sets. If it calls for three sets of ten at 70%, that is 139.2 kg for ten reps, three times, with 90 seconds of rest. The table above is the only arithmetic you need; the programme supplies the sets, reps and rest.
What you should lift for other rep counts
The same estimated max can be turned back into a target load for any rep count, using the Epley formula in reverse. The table below shows the load that corresponds to the 198.8 kg estimate for each standard rep count. Use it when a programme asks for a set of a different size than the 12-rep set this page started from.
| Reps | Target load (kg) | Target load (lb) |
|---|---|---|
| 3 | 180.7 kg | 398 lb |
| 5 | 170.4 kg | 376 lb |
| 6 | 165.7 kg | 365 lb |
| 8 | 156.9 kg | 346 lb |
| 10 | 149.1 kg | 329 lb |
| 12 | 142.0 kg | 313 lb |
| 15 | 132.5 kg | 292 lb |
| 20 | 119.3 kg | 263 lb |
Two warnings apply to this table. First, the loads for 15 and 20 reps are the least reliable, because they are extrapolated furthest from a heavy set. Second, the table assumes the same technique standard throughout — if your form changes at higher reps, the numbers stop comparing cleanly. Even so, the table is useful for planning: it tells you that a set of 8 reps at around 156.9 kg and a set of 5 reps at around 170.4 kg are roughly the same effort, just expressed at different rep counts.
How to use the result, and how to progress safely
The hip thrust is a glute-dominant lift usually programmed for sets of 6–12 reps, often as the main glute movement of a lower-body session. It pairs well with a squat or a hinge, and it is one of the easiest lifts to progress in small, regular jumps.
Use the 198.8 kg figure as a planning number, not as a weight to attempt tomorrow. The safest way to use an estimated max is to base your training percentages on it for four to six weeks, then re-test with a fresh submaximal set and update the estimate. If the new set gives a higher estimate, your training weights go up; if it gives the same number, you have maintained; if it gives a lower number, you may be under-recovered and need a lighter week.
Progression should be small and regular. For the hip thrust, adding 2.5–5 kg to the bar when you complete all prescribed sets and reps is a sensible rule for most lifters. Doubling the jump because the estimate went up is a mistake — the estimate is an average of two formulas, and it carries error bars of several kilograms either way. Small jumps, repeated for months, are what build a large max; large jumps are what cause missed reps and injuries.
Warm up properly before any heavy set. For a hip thrust session, that means a general warm-up, then the empty bar or a light load, then 50% of your working weight for a few reps, then 70%, then your working sets — never jumping straight from the warm-up to a heavy load. And never test a true one-rep max alone, without spotters or safety bars. The whole point of estimating from a 12-rep set is that you never have to find out what your true max is by attempting it.
Recovery is part of the programme, not a break from it. The hip thrust stresses the glutes, hamstrings, and those muscles need 48–72 hours before they are trained hard again. Sleep, food and rest days are where the strength is actually built; the training session is just the stimulus. A lifter who adds weight to the bar every week while sleeping five hours a night will stall and then regress, and no formula can fix that. Strength training also needs enough food to support it: very-low-calorie diets undermine recovery and strength, and minimum safe intakes are 1,200 kcal/day for women and 1,500 kcal/day for men — never plan a diet below those floors without medical supervision.
What the number does NOT tell you
An estimated one-rep max is a useful number with clear limits. First, it is an estimate, not a measurement. Your true max can only be found by attempting a maximum lift, and the estimate can be off by 5–10% in either direction even from a good set. That is why the percentage table above should be treated as a guide: if 80% feels like 90% on the day, trust the feeling, not the table.
Second, the formulas assume good technique. A hip thrust performed with a shortened range of motion or momentum will produce a higher rep count than a strict set, and the formulas will reward that with an inflated max. Compare estimates only between sets done the same way. A 12-rep estimate is useful but less precise than one from 5–8 reps, so use it to set training loads and re-test with a heavier set when you can.
Third, a one-rep max says nothing about your health, your body composition or your overall fitness. It measures one thing — the most weight you can lift once in this movement — and a big number in one lift does not imply a big number in another, let alone general health. It also says nothing about injury risk: a lifter with a large estimated max and poor technique is closer to an injury than a lifter with a modest max and excellent technique.
Finally, the formulas are population tools. They were fitted to groups of lifters, and individuals vary. Some lifters are naturally better at high reps than at singles, and the formulas will underestimate their max; others are the opposite, and the formulas will overestimate. Over time you will learn your own pattern — whether your true max tends to sit above or below the estimate — and you can adjust your training percentages accordingly.
Frequently asked questions
What is my hip thrust 1RM if I lift 140 kg for 12 reps?
Using the worked example on this page: Epley gives 196.0 kg and Brzycki gives 201.6 kg, so the averaged estimate is 198.8 kg. That figure assumes the 12-rep set was taken close to failure with good technique. For your own weight and rep count, use the One Rep Max Calculator.
Which formula is better, Epley or Brzycki?
Neither is clearly better in general — that is why this page averages them. Epley (1985) tends to give slightly higher estimates at higher rep counts, while Brzycki (1993) is often a little more conservative. From sets of ten reps or fewer the two usually agree within a few kilograms, and the average is a sensible compromise. Above ten reps both become less reliable, and the gap between them — 5.6 kg on this page's set — is a warning sign rather than a detail to average away.
How accurate is a 1RM estimated from 12 reps?
Twelve reps is just beyond the range where Epley and Brzycki are at their best. The formulas were fitted mainly to sets of ten reps or fewer, so a 12-rep estimate carries a wider error band — treat the average as the middle of a range of several kilograms either way, and prefer a heavier, lower-rep set when you next re-test. A 12-rep estimate is useful but less precise than one from 5–8 reps, so use it to set training loads and re-test with a heavier set when you can. The estimate is best used to set training loads for a four-to-six-week block, then re-tested. It is not a substitute for a properly supervised max attempt if you genuinely need to know your true maximum, for example before a competition.
What weight should I train with for strength on the hip thrust?
Strength work is usually 85–95% of your estimated max. For a 198.8 kg max, that is 169.0 kg to 188.9 kg, for sets of 1–5 reps with three to five minutes of rest. For muscle growth, use 65–85% (129.2–169.0 kg) for sets of 6–12 reps. The full percentage table above covers every step from 50% to 100%.
Is the hip thrust better than the squat for glutes?
It is different, not simply better. The hip thrust loads the glutes hardest at full extension, where the squat is easiest, while the squat loads the glutes and quadriceps through a much larger range. Most good programmes include both. Use the hip thrust for focused glute work and the squat for overall leg strength, and do not drop one because the other feels stronger.
Related pages
Estimates only, not medical advice. Minimum safe intakes: 1,200 kcal/day women, 1,500 kcal/day men — consult a healthcare professional before a very-low-calorie diet.