Health & Fitness Calculators
Health and fitness calculators including BMI and calorie deficit planning tools for goal tracking. This category includes 4 free tools.
BMI Calculator
Calculate your Body Mass Index (BMI) instantly. Free BMI calculator for adults with health category breakdown.
Health & FitnessCalorie Deficit Calculator
Calculate how many calories to eat to lose weight. See your TDEE, daily target, and estimated goal date using the Mifflin-St Jeor equation.
Health & FitnessMacro Calculator
Calculate your daily macros — protein, carbs, and fat — based on your goals using the Mifflin-St Jeor equation.
Health & FitnessPregnancy Due Date Calculator
Calculate your estimated due date from your last menstrual period or conception date. See your current trimester and milestones.
Health & FitnessAbout Health & Fitness Calculators
Making informed decisions about your health — whether you're tracking body weight, planning a calorie deficit, or preparing for a major life event like pregnancy — requires accurate, evidence-based tools. Our health and fitness calculators use formulas validated by the World Health Organization, the CDC, and leading nutrition researchers.
BMI uses the standard formula (weight in kg divided by height in meters squared), while calorie estimates are derived from the Mifflin-St Jeor equation, which research shows is more accurate than the older Harris-Benedict formula for most adults. Pregnancy due date calculations are based on standard gestational age counting from the first day of the last menstrual period.
Health calculations are screening tools, not medical diagnoses. BMI does not distinguish between muscle and fat mass. Calorie needs vary based on individual metabolic rate, activity accuracy, and health conditions. Always consult a qualified healthcare professional before making significant changes to your diet, exercise routine, or health plan.
Frequently Asked Questions
What BMI is considered healthy?
The WHO defines a healthy BMI range as 18.5 to 24.9 for adults. Below 18.5 is classified as underweight; 25–29.9 is overweight; 30 and above is obese. These are population-level guidelines. Individual health depends on many factors beyond BMI, including body composition, fitness level, age, and metabolic health.
What is a calorie deficit and how large should mine be?
A calorie deficit means consuming fewer calories than your body burns. A deficit of 500 calories per day generally produces roughly 1 lb of fat loss per week (3,500 calories ≈ 1 lb of fat). Aggressive deficits above 1,000 calories/day can cause muscle loss and metabolic adaptation — a moderate deficit of 300–600 calories/day is typically more sustainable.
How is a pregnancy due date calculated?
The standard method counts 280 days (40 weeks) from the first day of your last menstrual period. This is Naegele's rule, which assumes a 28-day cycle and ovulation on day 14. If your cycle is shorter or longer, actual conception and due date may differ. An ultrasound in the first trimester provides the most accurate dating.
Are BMI calculators accurate for athletes and older adults?
BMI is less accurate for people with high muscle mass (athletes may show 'overweight' BMI despite low body fat) and older adults (who may have normal BMI but reduced muscle mass). For these groups, metrics like waist circumference, body fat percentage, or DEXA scan results provide more meaningful health information.