Bench Press 1RM Calculator

Estimate your one-rep max (1RM) bench press from the weight and reps of a submaximal set, and read off your working weights across the full percentage table.

Quick Facts

Method
Epley formula: 1RM = weight × (1 + reps / 30)
Most accurate for sets of 2-6 reps; less precise above 10 reps.

Your Results

Calculated
Estimated 1RM (Epley)
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One-rep max from your set
Estimated 1RM (Brzycki)
-
Alternate formula for comparison
Estimated 3RM
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~93% of 1RM
Estimated 5RM
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~87% of 1RM

Ready

Enter the weight and reps of a recent hard set, then calculate.

About the Bench Press 1RM Calculator

Your one-rep max (1RM) is the heaviest weight you can bench press for a single clean repetition. Testing a true 1RM is fatiguing and, done alone or without a spotter, risky. This calculator estimates your 1RM from a set you can already do safely: enter the weight and the number of reps you completed to failure (or close to it), and it returns your projected max plus a full percentage-of-1RM loading table for planning your training.

The formula: Epley

The calculator uses the Epley formula:

1RM = weight × (1 + reps / 30)

For example, 185 lb for 5 reps gives 185 × (1 + 5/30) = 185 × 1.1667 ≈ 215.8 lb. Notice that at reps = 1 the formula returns the weight itself (185 × (1 + 1/30) is actually 191.2, so Epley treats a true single as slightly under the projected max — this is why estimates are calibrated to multi-rep sets, not singles). The formula assumes an inverse-linear relationship between load and the reps you can perform: heavier weight, fewer reps.

Brzycki, for comparison

The calculator also reports the Brzycki estimate, 1RM = weight × 36 / (37 - reps). Epley and Brzycki agree closely at low reps and diverge as reps climb: Brzycki tends to predict a slightly lower 1RM above roughly 10 reps. Seeing both gives you a realistic range rather than a single false-precision number.

Reps-to-percentage reference

Strength coaches use a rough reps-to-percentage chart to prescribe working weights. Common benchmarks: 1 rep ≈ 100% of 1RM, 2 reps ≈ 95%, 3 reps ≈ 93%, 5 reps ≈ 87%, 8 reps ≈ 80%, 10 reps ≈ 75%, 12 reps ≈ 70%, 15 reps ≈ 65%. The table this calculator generates uses these values so you can read off, say, what weight to use for a target set of 8.

Using your 1RM to program training

Once you know your estimated 1RM, most percentage-based programs work from a slightly reduced "training max" — Jim Wendler's 5/3/1, for instance, uses 90% of your tested or estimated 1RM as the training max and builds working sets off that. Starting from a conservative training max leaves room to progress week over week instead of grinding maximal singles every session.

Frequently Asked Questions

How accurate is an estimated 1RM?
Formula estimates are most accurate for sets of about 2 to 6 reps, typically landing within a few percent of a true tested max. Accuracy falls as reps rise: above 10 reps, muscular endurance and fatigue resistance matter more than raw strength, so the projection can be off by 10% or more. For the tightest estimate, use the heaviest weight you can honestly do for 3 to 5 reps.
Which formula should I trust, Epley or Brzycki?
Neither is "correct" — they are both regression fits to population data, so individual results vary. At low reps they agree within a pound or two. Above 10 reps, Brzycki usually reads lower. Treat the two numbers as the ends of a plausible range and, when it matters, verify with an actual heavy set rather than a single formula.
Do I have to lift to failure for the estimate to work?
The formulas assume the set was taken to (or very near) momentary failure — that the reps you entered are genuinely the most you could do at that weight. If you stopped with reps in reserve, the calculator will underestimate your 1RM. Enter only sets where you were within a rep of failure.
Should I ever test a true 1RM?
Estimates are ideal for everyday programming. A tested max is worth doing occasionally for competition or benchmarking, but always with a spotter or in a power rack with safety pins, a proper warm-up ramp, and full recovery beforehand. Never chase a true single alone on a flat bench with the bar over your throat.

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