Free fitness calculators that show their work

Four free calculators that show their formulas and say where they are wrong. They run entirely in your browser: nothing is stored and nothing is sent anywhere.

Adaptive TDEE

Estimates your real maintenance calories from your average intake and your weight change over at least a week, rather than from age and height.

Next-set weight

Takes the set you just finished, the reps you had left, and your target rep range, and suggests the next load rounded to real plates.

Daily protein

The evidence-based daily range (1.6-2.2 g/kg, higher on a cut) from your body weight and goal, not one suspiciously precise number.

Plate loading

Turns a target weight into plates per side, largest first, and says when the target is not expressible with standard plates.

Where they are wrong

Every tool shows its formula and its limitations. A calculator sees one snapshot; it knows nothing about your fatigue or your history.