One-rep max calculator.
Enter a weight and rep count, get your estimated max with a full percentage table.
Lift
Estimated bench press 1RM
262.5 lb
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Training percentages
The five formulas, compared.
Each formula was developed from different data sets, which is why they disagree at higher rep ranges.
Epley (1985)
The most cited formula. Works well across 3-10 reps. Slightly overestimates at very high rep ranges. Good default if you are unsure which to pick.
Brzycki (1993)
Matches Epley closely in the 3-5 rep range. Overestimates noticeably above 8 reps. The formula becomes undefined at 37 reps (the denominator hits zero), which is why the calculator clamps it. Above 15 reps the result is treated as invalid.
Lombardi (1989)
Conservative at low rep counts. Designed for sets of 10 or more. If your training mostly runs above 8 reps, Lombardi tends to give more conservative, more trustworthy results.
O'Conner et al. (1989)
Linear formula with a smaller slope than Epley. Consistently lower estimates, which some coaches prefer as a conservative floor. Useful if your Epley estimates always feel too optimistic.
Wathan (1994)
Uses an exponential curve. Originally included body weight as a variable; this implementation uses the simplified form. Performs well across a broad rep range for experienced lifters.
Works for any barbell lift.
The formulas are mathematically lift-agnostic. They hold up best on the four main barbell movements. Once you have a max for each, the strength ratio calculator shows whether your squat, bench, and deadlift move together or one has fallen behind.
Bench press
A 225 lb bench for 5 reps estimates to roughly 253 lb with Epley. Most programs set work sets at 80-85% of that, so around 200-215 lb for 4-6 rep sets, and a plate breakdown for each side turns that into bar math.
Squat
315 lb for 3 reps comes out near 340 lb. From there, 70% (238 lb) is a typical hypertrophy volume day and 90% (306 lb) for a heavy single on a peaking week.
Deadlift
405 lb for 2 reps estimates to around 432 lb. Because deadlift CNS cost is high, most programs keep daily top sets at 85-90% and pull a true max only once per training cycle.
Overhead press
135 lb for 5 reps puts the 1RM near 152 lb. OHP numbers are smaller, so the percentage table is especially useful for keeping volume sets from piling up junk at too low an intensity.
Using percentages in your training.
Your estimated 1RM is a programming tool, not a trophy. The table matters more than the top number. Percentages are one way to set intensity; an approach based on reps in reserve is another when daily readiness moves around. If you don't already have a program built around these numbers, the program quiz sorts out which track fits your goal and schedule in about a minute.
Maximal strength
Near-max singles, doubles, triples. High CNS demand. Reserve for peaking phases.
Strength work
3-5 rep sets. Where most powerlifting-style programs live. High mechanical tension.
Hypertrophy
6-12 rep ranges. Enough metabolic stress to drive muscle growth without excessive joint load.
Technique and volume
High-rep sets, speed work, technique practice. Useful for beginners and deload weeks.
When not to test your true 1RM.
A true max attempt requires near-perfect technique under full fatigue at a load you have never lifted. Attempting one without a structured peaking phase, a trained spotter, and established movement patterns is how injuries happen.
Calculated estimates from a solid 3-5 rep set are good enough for 95% of programming decisions, which is the whole case for estimating your max without a true max attempt. Use an actual 1RM test for competition, or at the end of a 12-16 week peaking block where you have been systematically preparing for it.
Why accuracy drops above 10 reps.
Below 6 reps, failure is almost always a strength limit. Above 10, cardiovascular capacity, local muscular endurance, and mental tolerance start to account for more of the result. A 20-rep set tells you something meaningful about work capacity, but almost nothing precise about your 1RM. The formulas were calibrated on low-rep data and extrapolate poorly at higher rep counts.
Common questions.
Reasonably accurate at 3-5 reps, less so above 8. The formulas were built from barbell-sport data, so they hold up best on compound lifts like squat, bench, and deadlift. Accessory lifts, cable machines, and bodyweight movements produce noisier estimates. Treat the number as a programming guide, not a competition total.
Epley is the default and the most widely cited. Brzycki matches closely at low rep ranges (3-5) but overestimates at higher reps. Lombardi was designed for sets above 10 reps. O'Conner is conservative and works well if your estimates consistently feel too high. Wathan takes body composition into account. If you're new to 1RM estimation, start with Epley and adjust from there.
Yes, with caveats. Results are most reliable for bilateral barbell movements with a fixed range of motion: squat, bench press, deadlift, overhead press, barbell row. Dumbbell lifts, cable exercises, and machines all have different fatigue curves that the formulas don't account for. The estimates still give a useful ballpark for planning, just expect more variance.
Testing a true 1RM has real cost: CNS fatigue, higher injury risk, and the technical demands of near-maximal loads. For most training contexts, calculated estimates are good enough to program your percentages accurately. Save actual max attempts for competition prep, or a structured peaking phase where you've built up to it over several weeks.
Strength standards vary by lift and experience level. A 1x bodyweight bench, 1.5x squat, and 2x deadlift are common intermediate milestones. Advanced lifters typically reach 1.5x bench, 2x squat, 2.5x deadlift. These are rough guides, not rules - genetics, training history, and body proportions all matter. The more useful question is whether your numbers are improving over time.
From the journal.
How to Use RPE for Strength Training: A Lifter’s Guide.
RPE is the most useful number in lifting and the easiest to fake. How the scale actually works, why it beats fixed percentages on a bad day, and how to stop lying to yourself about your reps in reserve.
How to Calculate Your 1RM Without Maxing Out.
Five formulas. None of them agree. Most do not come from research. Here is what actually works, and why "which formula" might be the wrong question entirely.
Keep going.
Plate calculator.
What to load for any target weight, in lb or kg.
RPE calculator.
Convert rate of perceived exertion to training percentages.
Wilks score.
Bodyweight-adjusted total for comparing strength across weight classes.
DOTS score.
The IPF's newer bodyweight-adjusted scoring formula.
IPF GL points.
The IPF's official Goodlift score, in use at meets since 2020.
Volume calculator.
Weekly sets per muscle group, tonnage, and load management.
Strength ratio.
Screen your squat, bench, and deadlift to find the lift that is lagging.
Other comparisons.
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Strong nutrition tools and a real branded app at $99/mo.
Trainerize.
Gyms and studios that need branded apps and community tools.
TrueCoach.
Remote 1-on-1 trainers. The 5% payment fee adds up fast.
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