Bench Press Calculator
Estimate your bench press one-rep max (1RM) from any working set — no risky max-out attempt needed — and see suggested working weights for common rep targets.
Estimated 1RM (Epley)
116.7 kg
- Brzycki formula
- 112.5 kg
- Lombardi formula
- 117.5 kg
- O'Conner formula
- 112.5 kg
- Average of 4 formulas
- 114.8 kg
- 2-rep max (est.)
- 109.4 kg
- 3-rep max (est.)
- 106.1 kg
- 5-rep max (est.)
- 100.0 kg
- 8-rep max (est.)
- 92.1 kg
- 10-rep max (est.)
- 87.5 kg
These are estimates from your submaximal set, not a measured max. Epley (1985) is the most widely used formula; Brzycki, Lombardi and O'Conner are shown for comparison — they typically spread a few percent apart, and all agree less well above about 10 reps. The rep-max rows invert the Epley estimate to suggest working weights for common rep targets.
How to use this calculator
Choose kilograms or pounds, enter the weight you benched and the number of full reps you completed with it — ideally a set taken to failure or close to it. The calculator returns your estimated one-rep max using the Epley formula as the headline figure, with the Brzycki, Lombardi and O'Conner estimates alongside for comparison, then inverts the estimate into a rep-max table: the heaviest weight you can likely lift for 2, 3, 5, 8 and 10 reps. Estimates are most reliable when the input set is 10 reps or fewer — a 5-rep set predicts your max much better than a 15-rep one.
How the calculation works
All four formulas model the trade-off between load and repetitions. Epley (1985) adds 1/30th of the weight per rep: 1RM = w × (1 + r/30). Brzycki (1993) uses 1RM = w × 36/(37 − r), published in the Journal of Physical Education, Recreation & Dance. Lombardi (1989) uses a power curve, w × r^0.1, and O'Conner (1989) a shallower linear ramp, w × (1 + 0.025r). The formulas are unit-agnostic — the answer scales the same in kg or lb. Epley and Brzycki agree exactly at 10 reps (both give 4/3 of the lifted weight); below 10 reps Brzycki runs slightly lower, above 10 slightly higher. A single-rep set is treated as your measured max by definition. The rep-max table inverts Epley: weight for r reps = 1RM ÷ (1 + r/30), which corresponds to the familiar training percentages of roughly 94% for a double, 91% for a triple, 86% for 5 reps and 75% for 10.
Worked example
You bench 100 kg for 5 clean reps. Epley: 100 × (1 + 5/30) = 116.7 kg. Brzycki: 100 × 36/32 = 112.5 kg. Lombardi: 100 × 5^0.1 = 117.5 kg. O'Conner: 100 × 1.125 = 112.5 kg. The four estimates average 114.8 kg, so your true max is very likely in the low-to-mid 110s. Working weights from the Epley estimate: about 109.4 kg for a double, 106.1 kg for a triple, 100 kg for 5 (your input set, recovered exactly), 92.1 kg for 8 and 87.5 kg for 10.
Frequently asked questions
What is a one-rep max (1RM)?
Your one-rep max is the heaviest weight you can lift for a single repetition with full range of motion and acceptable form. It is the standard yardstick for strength: training programmes prescribe loads as percentages of 1RM (for example 5 reps at 85%), powerlifting is judged on it, and progress over months is easiest to see in it. You can measure it directly by working up to a true maximal single, or estimate it from a submaximal set — which is what this calculator does.
Why estimate 1RM instead of just testing it?
A true max attempt is the most demanding thing you can do in the gym: it needs a spotter or safety bars, a thorough warm-up protocol, and it carries a higher strain and injury risk than submaximal work — especially for newer lifters whose form breaks down under maximal load. It also costs recovery time that could have gone into training. An estimate from a hard set of 3–8 reps gets you within a few percent for programming purposes with none of those costs, which is why most coaches only test true maxes a few times a year, if at all.
Which 1RM formula is most accurate?
No single formula wins in every study. Epley (1985) is the most widely used and the default here; Brzycki (1993) is the other common standard and tends to predict slightly lower for sets under 10 reps — the two agree exactly at 10. Research on bench press specifically finds the major formulas cluster within about 2–5% of measured maxes when the input set is 6 reps or fewer. The honest answer is that the spread between the four estimates shown is itself a good picture of the uncertainty; the average row splits the difference.
How many reps should my input set be for the best estimate?
Fewer is better: a set of 2–6 reps taken to (or within a rep of) failure predicts 1RM most accurately, because the formulas were fitted mainly on low-rep data. Accuracy decays noticeably above 10 reps — high-rep sets test muscular endurance as much as strength, and lifters differ widely there. That is why this calculator caps input at 20 reps and flags 10 as the practical limit. A 12–15 rep set will still give you a ballpark figure, just treat it as a rough one.
Do these formulas work for squat and deadlift too?
Yes — the formulas are not bench-specific, and the same arithmetic is used for squat, deadlift, overhead press and most barbell lifts. Accuracy varies a little by lift: studies tend to find rep-based predictions slightly more accurate for bench press than for deadlift, where form and grip fatigue at higher reps skew the relationship. The load-per-rep trade-off also differs by individual muscle fibre make-up, so calibrate against your own history where you can.
What percentage of my 1RM should I train at?
It depends on the goal. Classic strength work sits at 80–90% of 1RM for 2–6 reps, hypertrophy programmes mostly use 65–80% for 6–12 reps, and muscular endurance work drops below 65% for 12+ reps. The rep-max table this calculator produces maps those percentages onto actual bar weights: the Epley inversion gives roughly 94% for 2 reps, 91% for 3, 86% for 5, 79% for 8 and 75% for 10. Programmes differ — always follow the percentages your specific programme prescribes.