Built a comprehensive fitness calculation library because every existing npm package was either abandoned or incomplete. Zero dependencies, ~20KB, full TypeScript, 85 tests.

Covers: BMI, BMR (3 formulas), TDEE, macros (6 diet presets), one-rep max (7 formulas), body fat, heart rate zones, calorie burn (30+ activities), running pace, race predictions, ideal weight, water intake, and unit conversions.

All formulas sourced from peer-reviewed research.

npm: https://www.npmjs.com/package/@finegym/fitness-calc GitHub: https://github.com/finegym-io/fitness-calc