Health Tools
BMI, BMR, body fat, macros and hydration estimates, each page naming the method it uses.
All Health Tools
BMI Calculator
Body Mass Index from height and weight, with the WHO band, the healthy weight range for your height, and where the index misleads.
Calorie Calculator
Maintenance calories from the Mifflin-St Jeor equation and an activity factor, with sex-aware floors applied to the weight-loss target.
BMR Calculator
Resting metabolic rate in kcal per day from Mifflin-St Jeor, broken out hourly and as a sedentary day. It is not an intake target.
Water Intake Calculator
A rule-of-thumb daily fluid figure: an adjustable millilitres-per-kilogram rate plus an adjustable allowance for each 30 minutes of exercise.
Ideal Weight Calculator
Devine, Robinson and Miller ideal body weight shown side by side, with the spread between the three reported as the real margin.
Body Fat Calculator
US Navy tape method in metric form, with ACE category bands and an honest margin of roughly three to four percentage points.
Protein Intake Calculator
Daily protein in grams from body weight and goal, using 0.8 to 2.0 g/kg with the research behind each band set out plainly.
Pregnancy Due Date Calculator
Naegele's rule with a cycle-length adjustment: estimated due date, current gestation, trimester and an estimated conception date.
Macro Calculator
Split a daily calorie target into protein, carbohydrate and fat grams using Atwater factors of 4, 4 and 9 kcal per gram.
What to know about health tools
Each of these applies a specific published equation, and the page names it: BMI uses the WHO definition, resting metabolic rate uses Mifflin-St Jeor, body fat uses the US Navy circumference method, and estimated due dates use Naegele's rule. If you know which method produced a number, you can look it up instead of simply having to trust it.
All of them are population averages applied to an individual. They can't see muscle mass, medical conditions, medication, or anything about how you actually live. That's why a very muscular person often reads as overweight by BMI, and why a normal reading rules nothing out.
Nobody with medical training has reviewed these pages. Use them to get your bearings, then talk to a doctor or a registered dietitian before you change how you eat, train or medicate.
Frequently asked
Is BMI accurate for an individual?
It was designed to describe populations, not people. It uses only height and weight, so it can't tell muscle from fat: an athlete and a sedentary person of the same build get the same score. Treat it as one rough indicator among several.
Which of these numbers should I actually act on?
None of them on their own. They're starting points for a conversation with a clinician, who can weigh them against your history, bloodwork and circumstances.
Are my measurements stored or sent anywhere?
Nothing is transmitted. Values may be kept in your own browser so a refresh doesn't lose them. On a shared computer, use the clear button on the privacy page when you're done.