Health and Fitness Calculators

These calculators cover the health numbers people check most: BMI, daily calories and TDEE, body fat, macros, a pregnancy due date, your fertile window, heart rate training zones and blood pressure categories. Each one names its method, such as the Mifflin-St Jeor equation for calorie needs, the US Navy tape-measure method for body fat, Naegele's rule for due dates and the Karvonen formula for heart rate zones.

Treat the results as estimates and screening numbers, not a diagnosis. BMI cannot tell muscle from fat, calorie targets are starting points to adjust against your real results, and a due date is a best guess from your cycle dates. Use them to understand your numbers and to bring better questions to your doctor, not in place of medical advice.

Your weight, cycle dates and readings are calculated in your browser and are not uploaded.

20 free tools in this category. All run in your browser with no signup.

BMI, body fat and healthy weight

Check your BMI in pounds or kilograms, estimate body fat from a few tape measurements, and compare ideal weight formulas, lean body mass and waist-to-hip ratio.

BMI CalculatorFree BMI calculator for adults: enter height and weight in feet and pounds or cm and kg to see your BMI, CDC category, and healthy weight range.Body Fat CalculatorFree body fat calculator using the US Navy tape method: enter height, waist, neck, and hip to estimate body fat percentage, fat mass, and lean mass.Ideal Weight CalculatorFind your ideal body weight for your height and sex with the Devine, Robinson, Miller and Hamwi formulas, plus the healthy BMI range in lb or kg.Lean Body Mass CalculatorEstimate your lean body mass, fat mass and body fat with the Boer, James and Hume formulas in kg or lb, plus a Katch-McArdle BMR estimate.Waist-to-Hip RatioCalculate your waist-to-hip ratio from waist and hip measurements in inches or centimeters and compare it with the WHO cut-offs for men and women.

Calories, macros and weight loss

Estimate how many calories you burn in a day, split them into protein, carbs and fat, plan a deficit to reach a goal weight by a set date, and see what a workout burns using MET values.

Calorie & TDEE CalculatorFree calorie calculator that finds your BMR and TDEE with the Mifflin-St Jeor equation and shows daily calories to lose, maintain, or gain weight.Macro CalculatorFree macro calculator for daily protein, carbs, and fat in grams, with keto, low carb, and high protein presets and a per-meal breakdown by goal.Weight Loss CalculatorFind the daily calorie deficit, weekly loss rate and calories to eat to reach your goal weight by a target date, or get a finish date from a weekly rate.Calorie Burn CalculatorEstimate calories burned for 76 activities from your body weight and minutes, using MET values from the 2024 Compendium of Physical Activities.

Pregnancy, ovulation and period calculators

Estimate a due date from your last period or your conception date, predict your fertile window, and see your next six expected period dates. No account is needed.

Pregnancy Due Date CalculatorFind your due date from your last period, conception date or IVF transfer date, with your week of pregnancy, trimester and milestone dates.Ovulation CalculatorEstimate your ovulation day, 6-day fertile window, next period and due date from your last period and cycle length, plus your next three cycles.Period TrackerPredict your next 6 periods from your last period and cycle length, find your average cycle from earlier dates, and optionally save them on this device.

Running, strength and heart rate training

Set five heart rate zones from your resting and maximum heart rate, estimate a one rep max from a set you have already lifted, and get race pace and splits from a 5K up to a marathon.

Heart Rate ZonesCalculate your five heart rate training zones from age and resting heart rate using Karvonen or percent of max, with 220 minus age, Tanaka or Gellish.One Rep Max CalculatorEstimate your one rep max from a set of up to 20 reps using the Epley, Brzycki and Lander formulas, with a chart of training loads by percentage.Marathon Pace CalculatorWork out the pace per mile and per km for a 5K, 10K, half marathon or marathon, with mile or km splits, finish time from pace and a race time predictor.

Sleep, hydration and alcohol

Find bedtimes that line up with 90-minute sleep cycles, set a daily water goal for your weight and activity, and convert any drink into UK units and US standard drinks.

Sleep CalculatorFind the best bedtime or wake-up time from 90-minute sleep cycles, and adjust for how long you take to fall asleep and how long your cycles run.Water Intake CalculatorEstimate how much water to drink each day from your weight, activity level and climate, in ounces, liters and glasses, with a National Academies check.Alcohol Units CalculatorTurn any drink size and ABV into UK units, US standard drinks, grams of pure alcohol and calories, with NHS, US, Canadian and Australian guidelines.

Blood pressure and cholesterol

See which American Heart Association category a blood pressure reading falls in, and work out total-to-HDL and LDL-to-HDL cholesterol ratios from a lipid panel.

Blood Pressure CalculatorCheck your blood pressure category from your top and bottom numbers using the AHA ranges, with pulse pressure and mean arterial pressure.Cholesterol Ratio CalculatorCalculate your total cholesterol to HDL ratio, LDL to HDL ratio and non-HDL cholesterol in mg/dL or mmol/L, with plain-language reference ranges.

Frequently asked questions

What is the difference between BMR and TDEE?

BMR (basal metabolic rate) is the number of calories your body burns at complete rest. TDEE (total daily energy expenditure) is your BMR multiplied by an activity factor, so it estimates what you burn on a normal day including movement and exercise. The calorie and TDEE calculator works out BMR with the Mifflin-St Jeor equation and then applies the activity level you choose.

Is BMI accurate for muscular people?

Not always. BMI uses only height and weight, so a muscular person can land in the overweight range without carrying extra fat. A measurement-based estimate such as the body fat calculator, which uses the US Navy method, gives a fuller picture alongside BMI.

How is a pregnancy due date calculated?

The standard method, Naegele's rule, adds 280 days (40 weeks) to the first day of your last menstrual period and assumes a 28-day cycle. The due date calculator adjusts for longer or shorter cycles and can also start from a conception date. An early ultrasound can change the estimate, so go by the date your provider gives you.

What is a normal blood pressure reading?

Under the American Heart Association categories, normal is below 120 systolic and below 80 diastolic. A systolic reading of 120 to 129 with diastolic below 80 is elevated, and 130/80 or higher is high blood pressure. If a reading is above 180/120, wait a few minutes and measure again. If it is still that high, contact your doctor right away, and call 911 if you also have chest pain, shortness of breath, numbness, weakness, vision changes or trouble speaking.

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