One Rep Max Calculator
Estimate your 1RM and training loads
Estimate your one-rep max from a set you've done, then see suggested training weights at 70%, 80% and 90%.
How it works
We use the Epley formula: 1RM = weight × (1 + reps/30). It's most accurate for sets under about 10 reps. Use the percentage loads to program your training without maxing out.
Lift safely — use a spotter and proper form when testing heavy.
Frequently asked questions
How accurate is an estimated 1RM?
Quite accurate for sets of 2–10 reps; accuracy drops on very high-rep sets.
Should I actually test my 1RM?
Estimating from a submaximal set is safer for most lifters than a true one-rep attempt.