Bench Press 1RM Calculator

Your bench press one-rep max is the heaviest weight you can press off your chest to full lockout for a single rep. Because a true bench max can pin you under the bar, most lifters estimate it from a hard set of 3–5 reps instead. This calculator takes the weight you pressed and the reps you completed, runs them through four proven formulas (Epley, Brzycki, Lombardi, O'Conner), and averages the results for a dependable bench 1RM.

How to Test Your Bench Max Safely

The bench press is the lift where a failed rep is most dangerous, because the bar comes down across your throat and chest. Use the estimate instead of a true max whenever possible, and follow these rules:

1. Always use a spotter or, if alone, set the safety pins/arms of a power rack just below your chest level.
2. Never use collars when benching alone without safeties — if you fail, you can tip the bar to slide plates off one side.
3. Warm up in steps: empty bar, then ~50%, ~70%, ~85% of your target before the working set.
4. Test with a 3–5 rep set, not a single. A clean triple gives an estimate within a few percent of your real max with far less risk.
5. Keep form strict: shoulder blades retracted, feet planted, controlled descent, pause is optional but full lockout counts.

The Formulas Behind the Estimate

The calculator averages four equations (w = weight, reps = clean reps):

Worked Bench Example

You bench 80 kg for 4 reps:

• Epley: 80 × (1 + 4/30) = 90.7 kg
• Brzycki: 80 × 36/33 = 87.3 kg
• Lombardi: 80 × 4^0.10 = 91.5 kg
• O'Conner: 80 × (1 + 4/40) = 88.0 kg

Average ≈ 89.4 kg estimated bench 1RM. Round down to 89 kg or 87.5 kg when programming to leave a margin.

Bench Training Percentages

Once you know your bench 1RM, this table tells you what to load for a given rep target.

Common Bench Rep-to-Max Questions

• If I bench 100 kg for 1, what should I do for 8? About 75% = ~75 kg.
• How many reps at 80% of my bench? Roughly 8 reps for most lifters.
• My estimate from a 12-rep set seems high — why? High-rep bench sets are limited by endurance and tricep fatigue, which inflates the prediction. Re-test with 3–5 reps.
• Should I add a margin? Yes — program 2.5–5 kg below the estimate, especially when training without a spotter.

Note: This estimate is for training and informational use only. The bench press carries real injury risk under maximal loads — always train with a spotter or rack safeties, and consult a qualified coach or healthcare professional before testing a true max.