Use the calculator first, then check the assumptions. Every tool gives you a useful number and the reasons not to worship it.
Filter by training area, then open the calculator for method notes and caveats.
Estimate your one-rep max without turning every training day into a max-out day.
Turn RPE into a practical load estimate without pretending effort ratings are laboratory instruments.
Estimate cardio zones while keeping the limitations of heart-rate formulas in plain sight.
Convert one recent race or time trial into a realistic pace target for another distance.
Estimate calories and macros without pretending a formula knows your whole metabolism.
