Health Calculators
Understand your body using formulas cited by health authorities like WHO, CDC, NHS and ACOG — not guesswork. These 11 calculators cover body composition, nutrition, pregnancy and fertility, and lifestyle. No signup, no data stored — everything runs in your browser.
Body Composition
BMI calculator
Body mass index with healthy weight range guide.
Ideal weight calculator
Healthy weight range for your height, men and women.
Body fat calculator
Estimate body fat percentage using the US Navy method.
Nutrition
Calorie calculator
Daily calories to maintain, lose or gain weight.
Macro calculator
Daily protein, carbs and fat targets for your goals.
Pregnancy & Fertility
Due date calculator
Estimate your pregnancy due date week by week.
Ovulation calculator
Estimate your fertile window and next period date.
Conception calculator
Estimate your likely conception date.
Pregnancy weight gain
Healthy weight gain range based on your BMI.
Lifestyle
Sleep calculator
Find the best bedtime or wake-up time by sleep cycle.
Blood alcohol calculator
Estimate BAC using the Widmark formula.
How to choose the right health calculators
If you're checking a general weight-health screening number, start with the BMI calculator — it's the standard WHO/CDC screening metric. For a more personalized healthy range, the ideal weight calculator adjusts for your height and sex, and the body fat calculator (US Navy method) goes a step further by estimating composition rather than just total weight.
For nutrition planning, the calorie calculator (Mifflin-St Jeor equation) tells you how many calories to eat to maintain, lose or gain weight. Once you have that number, the macro calculator splits it into protein, carbs and fat targets based on your specific goal.
Pregnancy and fertility tools follow a natural order: the conception date calculator or ovulation calculator help before or around conception; the due date calculator (ACOG method) estimates delivery date once pregnancy is confirmed; and the pregnancy weight gain calculator tracks a healthy gain range based on your pre-pregnancy BMI throughout.
For lifestyle questions, the sleep calculator works backward or forward through 90-minute sleep cycles to suggest a bedtime or wake-up time, and the blood alcohol calculator (Widmark formula) estimates BAC from drinks, body weight and time elapsed.
Frequently asked questions
Are these health calculators medically accurate?
They use standard, published formulas cited by health authorities (WHO/CDC for BMI, Mifflin-St Jeor for calories, ACOG for due dates, Widmark for BAC). They're informational estimates, not a diagnosis — always consult a doctor or midwife for medical decisions.
Is my health data stored anywhere?
No. All calculations run entirely in your browser. Nothing you type — weight, height, dates — is sent to a server or saved. See our Privacy Policy for details.
Which calculator should I use to lose weight safely?
Start with the Calorie calculator to find your maintenance calories, then use the Macro calculator to set a moderate deficit with balanced protein, carbs and fat. Pair with the BMI or Body Fat calculator to track progress over time.
How accurate is the due date calculator?
It uses the standard ACOG method (40 weeks from your last menstrual period, or adjusted from a known conception date). It's an estimate — only about 5% of babies arrive on their exact due date — your doctor will refine it with ultrasound measurements.