Health Calculators
Track your wellness easily using our BMI calculator, calorie calculator, and water intake calculator. These tools are designed to support balanced living and accurate self-assessment.
About Our Health Calculators
Every health tool here runs on a named, documented method — not a black box. BMI uses the WHO/NIH classification (18.5–24.9 healthy range), calorie and TDEE estimates use the Mifflin-St Jeor equation published in the American Journal of Clinical Nutrition in 1990, and body fat uses the U.S. Navy circumference formulas from the Naval Health Research Center. Each calculator page states its formula, shows a worked example, and links to the primary source so you can check our math.
The honest caveat: these are screening estimates, not diagnoses. Equations built on population averages can misread individuals — a muscular person's BMI overstates their fat, and any BMR equation can miss by ±10%. Use the numbers as a starting point and confirm health decisions with a professional.
All 36 Health Calculators
- Army Body Fat Calculator Runs the U.S. Army's one-site tape equations from DA Forms 5500 and 5501 — abdominal circumference at the navel plus bod…
- BAC Calculator BAC calculator that estimates blood alcohol from standard drinks, body weight, sex and hours elapsed, with the 0.08 perc…
- BMI Calculator Divides your weight by the square of your height to give your body mass index, plotted against the WHO adult bands at 18…
- BMR Calculator Calculate your basal metabolic rate with the Mifflin-St Jeor equation — the calories your body burns at complete rest, p…
- Body Fat Calculator Estimates body fat from a tape measure — waist, neck and height, plus hips for women — using the U.S. Navy circumference…
- Body Fat Percentage Calculator Estimates body fat percentage from a tape measure — waist, neck and height, plus hips for women — using the U.S. Navy ci…
- Bra Size Calculator Bra size is a band number plus a cup letter. Enter your underbust and bust measurements in inches or centimeters and thi…
- Calorie Calculator Estimate the calories that keep your weight steady — Mifflin-St Jeor resting burn times an activity factor of 1.2–1.9.
- Calorie Deficit Calculator Calorie deficit calculator: enter your maintenance calories, pick a loss rate from 0.5 to 2 lb a week, and get the daily…
- Calories Burned Calculator Estimates the calorie cost of fifteen activities from your body weight and how long you moved, using the MET equation ex…
- Carbohydrate Calculator Carb calculator that turns a daily calorie figure into a carbohydrate range in grams, with a fiber target and an added-s…
- Chipotle Calorie Calculator Adds up a Chipotle order ingredient by ingredient — base, protein, rice, beans, salsa, toppings and sides — from Chipotl…
- Cow Gestation Calculator This calculator projects a cow's calving date from her breeding or artificial insemination date. Pick the gestation leng…
- DEXA Body Fat Estimator A DEXA scan measures body composition with a low-dose X-ray at a clinic. This page does not scan anything: it estimates …
- Gestational Age Calculator This calculator tells you how many weeks and days pregnant you are today. You can count from either of two dates: the fi…
- Heart Rate Zone Calculator This calculator works out the heart rate to aim for during a session, based on your age and what you want the session to…
- Height Calculator (Child Height Predictor) Predict a child's adult height from both parents' heights using the sex-adjusted mid-parental method, with the likely ra…
- Height Percentile Calculator This tool checks a height against the typical height of others of the same age and sex. Enter an age from 0 to 20 years,…
- Horse Gestation Calculator This calculator projects a mare's foaling date from her breeding or cover date. Choose the average gestation length you …
- Ideal Weight Calculator This calculator returns a weight range for your height using the four clinical formulas that turn up most often in pract…
- Macro Calculator Macro calculator that turns your daily calories into grams of carbohydrate, protein, and fat on a fixed 40/30/30 split, …
- NASM Calorie Calculator This calculator produces the daily calorie figure a NASM-certified trainer would work from. The method is not proprietar…
- Ovulation Calculator Places your estimated ovulation date 14 days before your next expected period, with the six-day fertile window that ends…
- Period Calculator This calculator projects the start dates of your next three periods. Enter the first day of your last period, your avera…
- Pregnancy Due Date Calculator Estimates your due date from a last period, a conception date or an IVF transfer, and shows how many weeks and days preg…
- Pregnancy Weight Gain Calculator This calculator gives the total pregnancy weight gain recommended for your pre-pregnancy body mass index, following the …
- Protein Calculator Multiplies your body weight in kilograms by a goal factor of 0.8, 1.4 or 1.9, then adds up to 20% for training load.
- Running Pace Calculator Turns a distance and a finish time into your average pace per kilometer and your average speed in km/h.
- Sleep Calculator A sleep calculator counts backward from the time you have to be awake in whole sleep cycles of about 90 minutes, so the …
- Starbucks calories calculator Adds up a Starbucks drink from its parts — a base that scales with cup size, the milk, 20 calories a syrup pump, whipped…
- Steps to Miles Calculator Convert steps to miles (or miles to steps) using a stride length estimated from your height — with the steps-per-mile ta…
- Subway Calorie Calculator Build your Subway order — sub, size, cheese, sauce, sides — and see the calories instantly, based on Subway's published …
- Taco Bell Calorie Calculator Add up the calories in your Taco Bell order — tacos, burritos, Crunchwraps, and sides — using the chain's published U.S.…
- TDEE Calculator Use our TDEE Calculator to know how many calories you burn daily. Plan your diet, fitness, or weight goals with accurate…
- Water Intake Calculator Turns body weight and age into a daily total water target — 33 mL per kilogram for adults — then splits it into what you…
- Weight Percentile Calculator Determine weight percentile in seconds. Simple inputs, accurate growth tracking—perfect for parents and health monitorin…
Where Most People Start
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BMI Calculator
The 10-second health screen: weight vs height against WHO categories, with a live gauge.
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TDEE Calculator
Your daily calorie burn — the number every diet plan should be built on.
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Body Fat Calculator
Tape-measure method that lands within 3–4 points of a DEXA scan.
Health Calculators — FAQs
How accurate are these health calculators?
Each tool uses peer-reviewed or institutionally-published formulas (WHO, NIH, the Mifflin-St Jeor equation, U.S. Navy body-fat method), and every page lists its sources. Accuracy is that of the underlying equation — typically within about 10% for calorie estimates and 3–4 percentage points for tape-measure body fat. They are screening tools, not medical diagnoses.
Which calculator should I start with?
Start with BMI for a quick weight-status check, then TDEE to learn your daily calorie burn, then the Macro Calculator to split those calories into protein, carbs, and fat. That chain — status, energy, plan — covers most fitness goals.
Is my health data stored anywhere?
No. All calculations run instantly in your browser — nothing you type is sent to or saved on our servers, and you can verify results disappear on refresh.