Question 1

What is a 1RM calculator?

Accepted Answer

A one-rep max (1RM) calculator estimates the maximum weight you can lift for a single repetition of a given exercise, based on the weight and reps you completed in a recent set.

Question 2

Which formula does this 1RM calculator use?

Accepted Answer

SmartyGym's 1RM calculator uses validated strength science formulas (Epley, Brzycki, Lombardi) so you get a reliable estimate without having to test a true one-rep max.

Question 3

Is the SmartyGym 1RM calculator free?

Accepted Answer

Yes. The 1RM calculator is 100% free, requires no signup, and works on any device at smartygym.com/tools/1rm-calculator.

Question 4

How accurate is a 1RM estimator?

Accepted Answer

Estimators are most accurate in the 2–10 rep range. Sets above 10 reps reduce accuracy because fatigue affects the bar speed and force output.