One-rep max calculator

Enter a set you completed. The calculator estimates the most you could lift for one rep, using two common formulas. Use pounds or kilograms. The page starts at 200 lb (90.7 kg) for 5 reps.

Units

Weight lifted

Reps performed

reps

Brzycki estimate: 225 lb (102.1 kg)
Epley estimate: 233 lb (105.8 kg)
100 percent of 1RM: 225 to 233 lb (102 to 106 kg)
95 percent of 1RM: 214 to 222 lb (97 to 101 kg)
90 percent of 1RM: 203 to 210 lb (92 to 95 kg)
85 percent of 1RM: 191 to 198 lb (87 to 90 kg)
80 percent of 1RM: 180 to 187 lb (82 to 85 kg)
75 percent of 1RM: 169 to 175 lb (77 to 79 kg)
70 percent of 1RM: 157 to 163 lb (71 to 74 kg)
65 percent of 1RM: 146 to 152 lb (66 to 69 kg)
60 percent of 1RM: 135 to 140 lb (61 to 64 kg)
55 percent of 1RM: 124 to 128 lb (56 to 58 kg)
50 percent of 1RM: 113 to 117 lb (51 to 53 kg)

This calculator is not medical advice and is for informational purposes only. Talk to a doctor or other qualified health professional about decisions that affect your health.

How it works

Brzycki is weight × 36 ÷ (37 − reps). Epley is weight × (1 + reps ÷ 30). At one rep both give the weight lifted. The page accepts 1 to 12 reps, because estimates from long sets drift. Each percentage line multiplies the estimates by that percent and shows the range from the lower to the higher one.

One-rep max example

200 lb for 5 reps. Brzycki: 200 × 36 ÷ 32 = 225.0 lb. Epley: 200 × (1 + 5 ÷ 30) = 233.3 lb. In kilograms that is 102.1 kg and 105.8 kg. Training at 80 percent means about 180 to 187 lb (82 to 85 kg).

Common questions

Which formula should I trust?

Neither is exact. They agree closely under about 10 reps. Use the lower number for planning.

Why cap reps at 12?

Estimates from long sets drift. Brzycki cannot be used at 37 reps or more.

Should I test a true max?

Only with a spotter and good form. An estimate is safer.

Do estimates work for every lift?

They are best for big barbell lifts. Isolation lifts vary more.