Max Bench Calculator
How it works
We use the Epley formula: 1RM = weight × (1 + reps/30), and show a Brzycki estimate as a cross-check. The working-set table inverts Epley to give the load for each rep count from your estimated max.
Rep-max estimates are most accurate at 10 reps or fewer — the further past a true single you go, the more the formulas drift.
Frequently asked questions
What is a one-rep max (1RM)?+
Your one-rep max is the heaviest weight you could lift for a single rep of an exercise. It's the standard benchmark for programming strength training as a percentage of your max.
How is 1RM calculated?+
This calculator uses the Epley formula: 1RM = weight × (1 + reps ÷ 30). It also shows a Brzycki estimate as a cross-check. Both estimate your max from a set you can actually complete, so you don't have to attempt a risky true single.
How accurate are one-rep-max calculators?+
They're most accurate at 10 reps or fewer. The further past a true single you go, the more fatigue and technique affect the estimate, so the numbers drift on high-rep sets.
What percentage of my 1RM should I train at?+
It depends on your goal: roughly 80–95% of 1RM for strength (1–5 reps), 65–80% for muscle growth (6–12 reps). Use the rep-max table above to find the load for each rep range.