Health Calculators — United States

How tall will my child be? Mid-parental height prediction with ranges, unit conversion and CDC context.

Estimate blood alcohol content by drinks, weight and time — with the 0.08%, Utah 0.05% and CDL 0.04% limits.

Open the Bmi Calculator and calculate instantly in your browser.

Open the Body Fat Calculator and calculate instantly in your browser.

Open the Body Mass Index Advanced Calculator and calculate instantly in your browser.

Open the Calorie Calculator and calculate instantly in your browser.

Your daily protein target in grams from bodyweight and goal, with a per-meal split and food equivalents.

Your max heart rate and five training zones from age — with the Karvonen resting-HR method for personal zones.

Estimate your one-rep max from any weight and reps — Epley, Brzycki and more — plus a %1RM training-load table.

Estimate your due date from your last period, conception date or IVF transfer — with gestational age and trimester.

Your fertile window and ovulation date from your last period and cycle length — with the best days to conceive.

Open the Carbon Footprint Calculator and calculate instantly in your browser.

Estimate the annual, decade-long, and lifetime cost of smoking, including opportunity cost.

Estimate your basal metabolic rate — the energy your body uses at complete rest — with the Mifflin-St Jeor equation, and compare it with Harris–Benedict.

Work out your total daily energy expenditure — maintenance calories — from BMR and an activity factor, with targets for losing or gaining weight.

Split a daily calorie target into grams of protein, carbohydrate and fat with a preset ratio or your own percentages.

See how long a daily calorie deficit takes to reach a target weight, using the 7,700 kcal-per-kilogram (3,500 kcal-per-pound) rule.

Divide your waist by your height to get the waist-to-height ratio, a simple screen for central fat that many studies find more useful than BMI.

Calculate your waist-to-hip ratio and compare it with the World Health Organization cut-offs for abdominal obesity (0.90 for men, 0.85 for women).

Estimate lean body mass — everything that is not fat — from height and weight with the Boer formula, compared with the James and Hume formulas.

Calculate body surface area with the Mosteller formula and compare Du Bois, Haycock and Gehan–George, the equations used for drug dosing and physiology.

Estimate an ideal body weight from height and sex with the Devine formula, alongside Robinson, Miller and Hamwi and the healthy-BMI weight range.

Estimate your maximum heart rate from age with the Tanaka formula (208 − 0.7 × age) and compare the classic 220 − age with Gellish and Nes.

Find the heart rate for a chosen training intensity with the Karvonen method, which uses your resting heart rate as well as your age, plus all five zones.

Turn a blood-pressure reading into mean arterial pressure and pulse pressure — the figures clinicians use for organ perfusion and arterial stiffness.

Pick a bedtime and see the wake-up times that land at the end of a 90-minute sleep cycle, after the minutes it takes you to fall asleep.

Count how many weeks and days pregnant you are from the first day of your last period, with the trimester, the estimated due date and the days to go.

Estimate how much caffeine remains in your body a given number of hours after a drink, using the average five-hour half-life, and when it falls below a level that could affect sleep.

Convert an HbA1c result into the estimated average glucose it represents, in mmol/L and mg/dL, and into the IFCC mmol/mol units, using the ADAG study equation.

Work out your total-cholesterol-to-HDL ratio and non-HDL cholesterol from a lipid panel, in mmol/L or mg/dL.

Estimate when conception is likely to have happened — from the last period, from a due date, or from how many weeks along a scan says you are.

The recommended weight-gain range for your stage of pregnancy, based on your weight before it began — with the weekly rate and where your current weight sits.

Turn a step count into distance and calories burned, using your weight and walking pace.

Classify your body shape from bust, waist and hip measurements — the categories clothing sizing uses.

The daily calories needed to gain weight at a chosen rate — with the surplus that adds muscle rather than mostly fat.

The calories that hold your weight steady — with the range the estimate really spans, and how it shifts as your weight changes.

BMI with the context that matters for women — body fat ranges, waist thresholds and why the same BMI means something different at different life stages.

BMI for men with the context it needs — the waist thresholds, an estimated body fat percentage, and why muscular builds read misleadingly high.

Body fat percentage from neck, waist and hip measurements — the US Navy circumference method, with its accuracy stated honestly.

Body fat estimated four different ways — BMI-based, Navy tape, RFM and skinfold — so you can see how much they disagree.

Weight change as a percentage of starting weight — the measure that makes progress comparable regardless of where you started.

BMI for children and teenagers, read against age and sex percentiles rather than adult thresholds — because the adult categories do not apply.

Your body frame size from wrist circumference and height — the measure that adjusts an ideal weight range for skeletal build.

Total body water from the Watson formula — how many liters you carry and what share of your weight it is.

How much sleep you have accumulated a deficit of, and how long it realistically takes to clear.