One-Rep Max Calculator

Estimate your max from the weight and reps you lifted

Weight lifted

Unit

Repetitions

Estimated 1RM (average)

Epley-

Brzycki-

Lombardi-

O'Conner-

Training weights by percentage

% 1RM	Approx. reps	Weight

These are estimates. The formulas track reality reasonably well at 10 reps or fewer and drift as reps increase. If you test a true max, always use a spotter.

Frequently asked questions

Why show several formulas?

There is no single 1RM equation; each rests on slightly different assumptions. Some track better at low reps, others stay steadier at higher ones. Reading the spread across several is closer to reality than trusting one number.

Why is the estimate worse at high reps?

As reps climb, endurance and technique matter more than raw strength. Extrapolating from a weight you can lift twelve or more times can land well away from your true max. Around five reps gives the most stable estimate.

How do I use the percentage table?

Broadly: 85%+ for low reps when training strength, 70–80% for moderate reps when training size, and around 60% for higher reps when training endurance. Exercises and individuals vary, so treat the table as a starting point.