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Bench Press Calculator

Our free bench press calculator estimates your one-rep max (1RM) from a set you have already lifted. Enter the weight on the bar and how many reps you did, pick a 1RM formula, and it works out your estimated max — with all five formulas shown side by side — plus the training weights to use for strength and muscle building.

How it works

Your one-rep max, or 1RM, is the heaviest weight you can bench press once with good form. Testing a true max is risky and tiring, so lifters usually estimate it from a lighter set they can already do. This calculator offers five 1RM formulas. Epley is the most widely used estimate in gyms and training programs across the United States. It assumes each extra rep you can do means your true max is a little higher than the weight in your hands.

Enter the weight you lifted, including the bar. A standard Olympic barbell weighs 45 pounds, so 185 pounds usually means the 45 pound bar plus 140 pounds of plates. Enter the number of reps you completed with good form, stopping when you could not do another clean rep. Choose pounds or kilograms; the formula works the same in either unit, and the answer comes back in the unit you picked.

With the Epley formula, one rep gives a max equal to the weight itself, since 1 + 1/30 is about 1.03, which is close to the weight you just lifted once. Five reps adds about 17 percent, ten reps adds 33 percent, and fifteen reps adds 50 percent. The estimate is most reliable for sets of 10 reps or fewer. Past 10 reps, endurance starts to matter more than raw strength, and the formula tends to guess high, so treat high-rep estimates with caution.

The formulas rarely agree exactly, and that is the point of showing all five. For 185 pounds for 5 reps, Epley gives about 216 lb, Brzycki about 208 lb, Lombardi about 217 lb, O'Conner about 208 lb, and Wathan about 216 lb — a spread of about 9 lb, or 4 percent. Brzycki and O'Conner tend to read lower, Lombardi a little higher, and Epley and Wathan usually land in the middle. No formula is right for everyone: Brzycki is popular with coaches, Lombardi suits low-rep sets, and Wathan was built from a large set of lifters' results. If the five estimates are close together, you can trust the middle of the range; if they spread widely, usually because the set was more than 10 reps, treat the whole estimate as rough and base your training weights on the lower end.

The training table below your max turns the estimate into a workout plan. Strength programs usually work at 80 to 90 percent of your max for 3 to 6 reps, while muscle-building programs use 65 to 80 percent for 8 to 12 reps. Warm-up sets sit around 50 to 60 percent. These are starting points, not rules: if the bar moves slowly and your form breaks down, the weight is too heavy for that rep range, whatever the percentage says.

Worked example

Say you benched 185 pounds for 5 clean reps at your gym in California. Here is the math, step by step.

First, divide the reps by 30: 5 ÷ 30 = 0.167. Add 1: 1 + 0.167 = 1.167. Multiply by the weight: 185 × 1.167 = 215.83, which rounds to about 216 pounds. That is your estimated one-rep max. The other formulas agree closely on this set: Brzycki and O'Conner both give about 208 lb, Lombardi about 217 lb, and Wathan about 216 lb. In practice you would not load 216 pounds and try it cold; you would work up to it with a spotter and safety bars.

From that 216 pound max, the training weights follow easily. Ninety percent is 216 × 0.90 = 194 pounds, a good weight for heavy sets of 3 to 5 reps. Eighty percent is 173 pounds, seventy percent is 151 pounds for sets of 8 to 12, and sixty percent is 130 pounds for warm-ups and higher-volume work. If you lift in kilograms, the same example is 84 kg for 5 reps, giving an estimated max of about 98 kg, since 84 × 1.167 = 98.

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