Health

Everyday health numbers, BMI, calorie needs, heart rate zones, sleep cycles, are all built on published formulas that most people have heard of but rarely calculate precisely, usually settling for a remembered rule of thumb instead. This category covers body-composition calculators (BMI, body fat, ideal weight), energy and activity calculators (BMR, TDEE, calorie deficit, macros), and other everyday health math (heart rate zones, sleep cycles, pregnancy due dates, water intake), each using the specific formula it's named after (Mifflin-St Jeor for BMR, the standard BMI formula, published heart-rate-zone percentages) rather than an approximation. These are useful for setting a realistic calorie target, understanding what a BMI number actually means for your specific body, or figuring out what heart rate range to train in for a specific fitness goal. None of these calculators are a substitute for advice from a healthcare professional, they're screening-level estimates using the same formulas doctors and trainers reference, made instantly accessible without needing to look up or manually compute the underlying equation yourself.