Health and fitness calculators
Body mass index, energy needs, body fat and weight ranges, calculated with the published formulas clinicians use — and an honest account of what each number can and can’t tell you.
9 calculators
Most used
- BMI CalculatorBody mass index from height and weight, with your weight class and healthy range.
- Calorie CalculatorDaily calories to maintain your weight, plus targets for losing or gaining at three steady paces.
- Due Date CalculatorEstimated due date from the last period, conception or IVF transfer, with weeks pregnant and term milestones.
- Macro CalculatorDaily grams of protein, carbohydrate and fat for your calorie target and chosen split, per day and per meal.
All health and fitness calculators
- BMI CalculatorBody mass index from height and weight, with your weight class and healthy range.
- Calorie CalculatorDaily calories to maintain your weight, plus targets for losing or gaining at three steady paces.
- BMR CalculatorBasal metabolic rate from three published equations, with daily calories at five activity levels.
- Body Fat CalculatorBody fat percentage from a tape measure, with fat mass, lean mass and the ACE category.
- Ideal Weight CalculatorFour published ideal body weight formulas side by side, with the healthy BMI weight range for your height.
- Macro CalculatorDaily grams of protein, carbohydrate and fat for your calorie target and chosen split, per day and per meal.
- Due Date CalculatorEstimated due date from the last period, conception or IVF transfer, with weeks pregnant and term milestones.
- Ovulation CalculatorEstimated ovulation day, fertile window and next period from your last period and cycle length.
- Pace CalculatorRunning pace, finish time or distance from the other two, with speed, even splits and race-time estimates.
What these numbers are for
Formulas like BMI and the Mifflin-St Jeor equation are population-level estimates. They are useful for tracking changes and starting conversations, but they don’t measure health directly. Muscle mass, age, sex, ethnicity, pregnancy and medical conditions all affect how a result should be read.
- Start with the BMI calculator for a quick weight-for-height screen.
- The calorie calculator estimates daily energy needs from your BMR and activity level; the macro calculator splits that target into protein, carbohydrate and fat.
- The due date calculator estimates a pregnancy due date from the last period, conception or IVF transfer date; the ovulation calculator estimates the fertile window from cycle length.
- Runners can work out pace, speed and finish times with the pace calculator.
- The body fat calculator uses tape measurements, which capture fat distribution better than weight alone.
These tools give general information for adults and are not medical advice.