One-rep max calculator

Training weight [kg] × (1 + Good-form reps ÷ 30). 1RM uses the Epley approximation; one repetition returns the entered load. High repetition counts are less accurate. The estimate is not an instruction to attempt a maximum lift.

For one repetition, the lifted weight is already the observed 1RM and is returned unchanged. For 2–15 repetitions Epley is used; higher repetition counts increase uncertainty.

The formula uses the specified units. Displayed numbers are rounded; whole packs, item counts and full time periods may also be rounded within the calculation. Health values are general information, not a diagnosis or personal treatment recommendation.

Yes. Calculations and PDF export work without an account or registration.

Calculations run in your browser. Results are saved locally only when you add them to My results; favourites and history are also local. Shared links contain your values. The currency tool requests the selected currencies from its rate provider without sending your amount.