One Rep Max (1RM) Calculator

Estimate your one-rep max from any set using five formulas, plus a training weight chart from 60% to 100%.

How do I calculate my one rep max?

Enter the weight you lifted and how many clean reps you did, and the calculator estimates your one-rep max with five established formulas, averages them and lists training weights from 60% to 100% of your 1RM with typical rep ranges.

Example

Benching 80 kg for 6 reps gives an estimated 1RM of about 93 kg (Epley: 80 × (1 + 6/30) = 96 kg; Brzycki: 80 × 36 / 31 = 93 kg).

Using percentages

85–95% for strength (1–5 reps).
65–80% for muscle growth (6–12 reps).
Below 65% for endurance and technique.

Frequently asked questions

Which formula is most accurate?

All are similar for 2–10 reps; the average is a good estimate.

Should I test a real max?

Only with good technique, a warm-up and a spotter.

Is it free?

Yes.