Strength · Epley + Brzycki
One-Rep Max
Estimate your 1RM from a set of 10 reps or fewer taken to failure, then read off your training loads.
Use a set you took to the point where you could not have completed another rep in good form. Both formulas are built on reps-to-failure: a set you stopped short will under-report your max, and one where your form broke down will over-report it. The slider stops at 10 because that is where Brzycki said his equation stops working.
The lb/kg control changes the label only — it does not convert your number. The formulas are unit-agnostic, so the answer comes out in whatever unit you typed in.
Estimated one-rep max
257.8lb
The mid-point of the Epley and Brzycki estimates. An estimate, not a tested max — an individual result can be off by around 10% either way, so treat it as the middle of a range.
The two estimates
Training loads
| Reps | % of 1RM | Load (lb) |
|---|---|---|
| 1 | 100% | 258 |
| 2 | 95% | 245 |
| 3 | 93% | 240 |
| 5 | 87% | 224 |
| 8 | 80% | 206 |
| 10 | 75% | 193 |
| 12 | 70% | 180 |
Percentages are the NSCA Training Load Chart, which is defined for 1–10 reps plus 12 — we do not publish loads past that, because no cited table covers them. Round down to the nearest plate. “Reps in reserve” applies to these prescribed loads, never to the set you typed in above.
At this load, the safety equipment is the equipment
Brzycki built the formula above so that lifters would not have to max out. If you are moving this much weight at home, the thing worth buying is not more plate — it is something that catches the bar when a rep does not go up.
CAP Barbell Power Rack Exercise Stand
J-cup catches and set pins mean a missed squat or press lands on steel instead of on you. Buy this before you test a single.
FLYBIRD WB5 Adjustable Weight Bench
An 800 lb-rated bench to pair with the rack, so the press has the same margin the squat does.
Read the write-ups behind these picks
- The affordable power rack we build home gyms around — what to look for in catches and pins
- 5 best home gym benches — rated by frame, padding and angle range
- Kettlebell vs dumbbell: which to buy first — if you are still choosing your load
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How this is calculated
Two published estimators, reported side by side, plus their mid-point. Epley: 1RM = weight × (1 + reps ÷ 30). Brzycki: 1RM = weight ÷ (1.0278 − 0.0278 × reps), which is the same as weight × 36 ÷ (37 − reps). A tested single is reported as itself rather than run through Epley, which would otherwise inflate it by 3%.
- 01Take the weight you lifted and the number of reps you got to failure.
- 02Run both formulas. They agree exactly at 10 reps and diverge either side of it — below 10 reps Epley reads higher.
- 03Report the mid-point as the headline estimate. Averaging the two is our own choice, not a published method: we do it because the mid-point stays within about 1% of the max implied by the NSCA Training Load Chart at every rep count from 1 to 10, while either formula alone drifts further.
- 04Build the load table by applying the NSCA Training Load Chart percentages to that estimate.
What this assumes
- · The set you enter was taken to failure. That is what "reps-to-fatigue" means in both source papers, and it is the single most common way this tool gets a wrong input.
- · Ten reps or fewer. Brzycki states his equation "is only valid for predicting a 1-RM when the number of reps-to-fatigue is less than 10", and his own table stops at 10. We cap the slider there rather than extrapolate.
- · Individual error of roughly ±10% even inside the valid range. The equations correlate strongly with tested maxes on average, but your result is the middle of a range, not a number.
- · The error is not uniform across lifts: these equations were derived largely from bench press data and tend to under-predict the deadlift and other lower-body compounds. An endurance-trained lifter will also get more reps at a given percentage than a powerlifter.
- · The formulas are unit-agnostic, so your answer carries whatever unit you entered. The lb/kg control is a label, not a conversion.
Sources
- [1]Brzycki, M. (1993). Strength Testing — Predicting a One-Rep Max from Reps-to-Fatigue. JOPERD 64(1):88–90 — the equation, its reference table, and the "fewer than 10 reps" limit
- [2]NSCA Training Load Chart (adapted from Landers, J., NSCA Journal 6(6):60–61, 1984) — the rep → %1RM percentages in the load table
- [3]Epley, B. (1985). Poundage Chart, in Boyd Epley Workout, p. 86 — the second estimate; reconstructed from a chart, never published as an equation
- [4]Mayhew, J.L. et al. (2008). Accuracy of prediction equations for determining one repetition maximum bench press. J Strength Cond Res 22(5):1570–1577 — prediction equations are more accurate below 10 reps-to-failure
Last reviewed October 2026
This is an estimate, not a weight to go attempt
Brzycki wrote this equation precisely so that lifters would not have to max out. In his own words, attempting a one-rep max with heavy weights “can place an inordinate and unreasonable amount of stress on the muscles, bones, and connective tissues”, and a 1RM attempt “tends to increase blood pressure beyond that which is normally encountered when using submaximal weights” — concerns he notes are magnified for adolescents and older adults. Testing from a submaximal set, he writes, “is much safer than a 1-RM lift”.
So use the number to program your working sets, not as a target to walk up and try. If you do test a true single, do it with a competent spotter or properly set safety pins, after a graded warm-up, with technique you have already proven over several sessions.
Exercise Legend is not a medical authority and this tool does not provide medical advice. If you have a cardiovascular condition, a blood-pressure concern or a current injury, talk to a clinician before maximal lifting.