Free health calculators

Instant, private tools for weight, heart, lifestyle, women’s and children’s health. No account needed — your inputs stay in your browser. Create a free account any time to save results and track trends.

27 free calculators · educational, not a diagnosis

Weight & body

Body mass index from your height and weight, with what your result means.

Calorie Calculator

Daily calories to maintain, lose or gain weight (BMR & TDEE).

Ideal Weight Calculator

Your healthy weight range for your height.

Waist-to-Height Ratio Calculator

A quick central-fat health check — often better than BMI alone.

Body Fat Calculator

Estimate body-fat percentage using the US Navy tape method.

Biological Age Calculator

See how your lifestyle nudges your body age above or below your real age.

Your basal metabolic rate — calories burned at rest — plus daily burn.

Macro Calculator

Split your calories into protein, carbs and fat, with a protein target.

Heart & circulation

Blood Pressure Checker

Find your blood-pressure category from a reading (AHA guidelines).

Cholesterol Ratio Calculator

Your total-to-HDL ratio, non-HDL and LDL cholesterol, with reference ranges.

Blood sugar & metabolic

Blood Sugar Converter

Convert glucose between mg/dL and mmol/L, with reference ranges.

HbA1c Calculator

Turn HbA1c into your estimated average glucose (eAG) and category.

Diabetes Risk Checker

A 1-minute type 2 diabetes risk score (FINDRISC-style).

Everyday lifestyle

Water Intake Calculator

How much water to drink a day for your weight, activity and climate.

Caffeine Intake Calculator

Add up your daily caffeine against the 400 mg safe limit.

Alcohol Unit Calculator

Count your weekly alcohol units against the 14-unit guideline.

Fitness

Heart Rate Zone Calculator

Your five training zones from your age (and resting heart rate).

Women's health

Ovulation Calculator

Estimate your fertile window and next period from your cycle.

Period Calculator

Predict your next three periods from your cycle.

Due Date Calculator

Your pregnancy due date and how many weeks you are, from your LMP.

Pregnancy Weight Gain Calculator

Recommended pregnancy weight gain for your pre-pregnancy BMI (IOM).

Children's health

Child Growth Percentile Calculator

WHO/CDC weight, height & head-circumference percentiles for babies and children.

Child BMI Calculator

BMI-for-age percentile for children and teens (2–18 years).

Baby Weight Percentile

Where your baby’s weight sits on WHO/CDC charts, from birth.

Baby Height / Length Percentile

Your baby’s length/height percentile on WHO/CDC charts.

Baby Head Circumference Percentile

Track head-circumference percentile — a key early-development marker.

Child Height Predictor

Predict a child’s adult height from the parents’ heights.