Fitness & Health Calculators
Essential health, fitness, and pregnancy calculators — each processed 100% locally in your browser.
BMI Calculator
Calculate your Body Mass Index (BMI), BMI prime, and healthy weight range for adults.
Open calculator →BMR Calculator
Estimate your Basal Metabolic Rate (BMR) using Mifflin-St Jeor and Harris-Benedict formulas.
Open calculator →Calorie Calculator
Calculate daily calorie targets for weight loss, maintenance, or weight gain based on activity level.
Open calculator →Body Fat Calculator
Estimate body fat percentage and lean body mass using the US Navy tape measure method.
Open calculator →Ideal Weight Calculator
Compare ideal body weight estimates across Devine, Robinson, Miller, and Hamwi medical formulas.
Open calculator →Running Pace Calculator
Calculate running pace per km or mile, average speed, and estimated race completion times.
Open calculator →Pregnancy Calculator
Track current gestational age, pregnancy trimester, and major fetal development milestones.
Open calculator →Pregnancy Conception Calculator
Estimate probable conception dates and fertile windows based on due date or period date.
Open calculator →Pregnancy Due Date Calculator
Calculate estimated birth due date using Naegele’s rule adjusted for cycle length.
Open calculator →Macro Calculator
Calculate optimal protein, carbohydrate, and fat macro ratios for fitness goals.
Open calculator →TDEE Calculator
Calculate Total Daily Energy Expenditure (TDEE) and physical activity energy output.
Open calculator →Target Heart Rate Calculator
Find heart rate training zones for fat burn, cardio, and peak performance.
Open calculator →One Rep Max Calculator
Estimate maximum 1RM weight limit for weightlifting exercises like squat and bench press.
Open calculator →Carbohydrate Calculator
Calculate daily carb intake needs based on fitness goals and body mass.
Open calculator →Protein Calculator
Calculate daily dietary protein requirements for muscle growth and endurance.
Open calculator →Fat Intake Calculator
Determine healthy daily dietary fat targets for hormonal health and keto diets.
Open calculator →Calories Burned Calculator
Estimate calories burned during physical exercises using MET values.
Open calculator →Lean Body Mass Calculator
Calculate lean muscle mass percentage using Boer, James, and Hume formulas.
Open calculator →Healthy Weight Calculator
Determine healthy target weight range based on WHO BMI criteria and body frame size.
Open calculator →Army Body Fat Calculator
Check the 2026 Army waist-to-height standard (under 0.55), with the 2023 tape test for comparison.
Open calculator →Pregnancy Weight Gain Calculator
Track recommended gestational weight gain targets by trimester.
Open calculator →Ovulation Calculator
Predict most fertile days and estimated ovulation dates in your menstrual cycle.
Open calculator →Period Calculator
Forecast upcoming menstrual cycle start dates and cycle lengths.
Open calculator →GFR Calculator
Calculate Glomerular Filtration Rate (eGFR) for kidney function assessment.
Open calculator →Body Type Calculator
Determine body shape (Hourglass, Pear, Rectangle, Apple) using bust, waist, and hip ratio.
Open calculator →Body Surface Area Calculator
Calculate total body surface area (BSA) using Mosteller and DuBois formulas.
Open calculator →BAC Calculator
Estimate Blood Alcohol Concentration (BAC) over time based on drinks consumed.
Open calculator →Weight Watcher Points Calculator
Calculate food smart points based on calories, saturated fat, sugar, and protein.
Open calculator →Water Intake Calculator
Estimate a daily fluid target from bodyweight, exercise and climate, in litres and cups.
Open calculator →Calorie Deficit Calculator
Turn a daily deficit into a weekly rate of loss and a realistic timeline to a goal weight.
Open calculator →Waist to Height Ratio Calculator
Screen for central obesity with the 0.5 boundary — keep your waist under half your height.
Open calculator →Waist to Hip Ratio Calculator
Assess fat distribution against the WHO cut-points of 0.90 for men and 0.85 for women.
Open calculator →Navy Body Fat Calculator
Estimate body fat from neck, waist and hip measurements using the US Navy tape method.
Open calculator →Maintenance Calorie Calculator
Find the daily intake that holds your weight steady — the number every other target builds on.
Open calculator →Keto Calculator
A ketogenic macro split with carbohydrate capped in grams and protein set from bodyweight.
Open calculator →FFMI Calculator
Fat-free mass index — muscle relative to height, normalised to a 1.8 m reference.
Open calculator →Weight Loss Percentage Calculator
Progress as a share of starting weight, including the 5% clinical threshold.
Open calculator →BMI Calculator for Women
BMI with WHO categories, plus what it misses about female body composition, pregnancy and menopause.
Open calculator →BMI Calculator for Men
BMI with WHO categories, and why it systematically misclassifies muscular builds.
Open calculator →RFM Calculator
Body fat from height and waist alone, using the Relative Fat Mass equation.
Open calculator →Skinfold Body Fat Calculator
Calliper readings through the Jackson-Pollock 3-site method and the Siri equation.
Open calculator →Ponderal Index Calculator
Weight over height cubed — holds up better than BMI at extremes of height.
Open calculator →Body Frame Size Calculator
Small, medium or large frame from height and wrist circumference.
Open calculator →Heart Rate Zone Calculator
Five training zones using the Karvonen method and the Tanaka maximum formula.
Open calculator →VO2 Max Calculator
Aerobic capacity from a Cooper 12-minute run or from resting heart rate.
Open calculator →Sleep Debt Calculator
Total a week of short nights and see how many recovery nights it takes to clear.
Open calculator →Caffeine Calculator
How much caffeine is still in your system, using the five-hour half-life.
Open calculator →Standard Drink Calculator
Convert any drink to grams of alcohol, US standard drinks and UK units.
Open calculator →Pack Year Calculator
Cumulative smoking exposure as packs per day multiplied by years smoked.
Open calculator →Sobriety Calculator
Days, weeks, months and years since your quit date, counted on the calendar.
Open calculator →Blood Type Calculator
Which ABO and Rh blood types a child can inherit from two parents.
Open calculator →Gestational Age Calculator
How many weeks and days pregnant, adjusted for cycle length.
Open calculator →Reverse Due Date Calculator
Work backwards from a due date to the likely conception window.
Open calculator →IVF Due Date Calculator
Due dates for day 3, 5 and 6 embryo transfers, where the embryo age is known exactly.
Open calculator →Implantation Calculator
The implantation window after ovulation, and why testing earlier cannot work.
Open calculator →Chance of Pregnancy Calculator
The chance of conceiving this cycle from the days you had sex, using published day-by-day rates.
Open calculator →DPO Calculator
Days past ovulation, the implantation window and when a pregnancy test is worth taking.
Open calculator →Drug Half-Life Calculator
How much of a single dose remains over time, and when it is about 97% eliminated.
Open calculator →Frequently asked questions
Are these fitness and health calculations medical advice?
No. All calculators provide estimates based on standard clinical and physiological formulas (such as Mifflin-St Jeor, Devine, and Naegele’s rule). They are intended for educational and wellness tracking purposes only.
How accurate is the US Navy Body Fat method?
The US Navy body fat tape measurement method is accurate to within 3–4% for most individuals compared to DEXA scans when measurements are taken precisely.
Is any of my health or personal data saved or uploaded?
No. Every calculation is processed 100% locally inside your web browser using client-side JavaScript. Zero health metrics are stored or transmitted.
How is pregnancy due date calculated?
Due dates are calculated using Naegele’s rule (280 days from the first day of your last menstrual period), adjusted for custom cycle lengths.