Health Calculators

Free online health and fitness calculators. All results are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before making decisions about your health.

Body & Weight

• BMI Calculator — Body Mass Index using WHO categories, metric and imperial units
• Calorie Calculator — Daily calorie needs using Mifflin-St Jeor with activity level multiplier
• BMR Calculator — Basal Metabolic Rate: calories burned at complete rest
• TDEE Calculator — Total Daily Energy Expenditure: BMR × activity factor
• Body Fat Calculator — Body fat percentage using the US Navy circumference method
• Ideal Weight Calculator — Devine, Robinson, Miller, and Hamwi formula comparison

Nutrition & Goals

• Macro Calculator — Protein, carbs, and fat targets based on TDEE and fitness goal
• Water Intake Calculator — Daily water needs based on weight and activity level
• Sleep Calculator — Optimal bedtime based on 90-minute sleep cycles
• Heart Rate Zone Calculator — Karvonen formula with 5 training zones
• BAC Calculator — Blood alcohol content estimate using Widmark formula. For informational purposes only — never drink and drive.

Women's Health & Fertility

• Pregnancy Calculator — Due date, trimester timeline, and key milestone dates from LMP
• Ovulation Calculator — Fertile window from LMP and cycle length
• Pace Calculator — Running pace from distance and time, with splits table for common race distances