Percentage of 1RM Calculator
Turn your one-rep max into a full percentage table of training weights, with the reps each intensity typically allows.
How it works
Weight = round(1RM × percent) · approx reps = 30 × (1RM ÷ weight − 1) (inverted Epley)
Programs prescribe load as a percentage of your one-rep max so intensity scales with your strength. Roughly, 85–95% builds maximal strength at low reps, 70–80% builds size in the mid-rep range, and 50–65% is used for technique, speed and recovery work. The rep estimates come from the Epley relationship and are approximate.
Worked example
With a 300 lb 1RM: 85% = 255 lb (about 5 reps), 70% = 210 lb (about 10 reps), and 50% = 150 lb for light speed work. Rounding to 5 lb keeps the numbers loadable on a standard bar.
Frequently asked questions
How accurate are percentage tables?
They are a solid starting point, but true rep capacity at a given percentage varies by lift and individual — most people can do more reps at a percentage on the leg press than on a heavy bench, for instance.
Should I base a whole program on my 1RM?
Many strength programs do, but they use a slightly reduced "training max" (often 90% of your true 1RM) so the percentages stay achievable across a training block.
What percentage builds muscle best?
Hypertrophy responds to a wide range, but roughly 65–80% of 1RM for 6–12 reps taken close to failure is the classic muscle-building zone.
Related calculators
Educational estimate for training planning, not medical or coaching advice. Warm up, use good form, and progress gradually — stop if you feel pain.