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MyFoodMate AI
Calculators

Calorie, macro, water and BMI calculators

Four calculations with clear formulas and caveats. We use widely accepted equations and are upfront about where they fall short.

Four calculators

  • Calorie needs

    /en/calculators/calories

    How many calories you need per day, using the Mifflin–St Jeor equation adjusted for activity and goal.

  • Macros

    /en/calculators/macros

    How many grams of protein, fat and carbs fit your calorie target and chosen balance.

  • Water intake

    /en/calculators/water

    How much fluid you need per day based on weight, activity and weather. All fluids count, not just water.

  • Body mass index

    /en/calculators/bmi

    Your BMI and what it means - with caveats about who this measure doesn’t work for.

How we calculate

Every calculator on the site uses the same formulas as the app. Basal metabolic rate is calculated with the Mifflin–St Jeor equation: today it is the standard for healthy adults and about 5% more accurate than the older Harris–Benedict formula.

BMR (women) = 10 × weight + 6.25 × height − 5 × age − 161BMR (men) = 10 × weight + 6.25 × height − 5 × age + 5

Weight in kilograms, height in centimetres, age in years.

The resulting BMR is multiplied by a physical activity factor - from 1.2 for a sedentary lifestyle to 1.725 for daily training. The result is your daily maintenance calories.

What these formulas don’t account for

  • body composition: at the same weight, a person with more muscle burns more;
  • thyroid conditions, certain medications, pregnancy and breastfeeding;
  • individual differences - two people with identical stats can burn 200–300 kcal apart.
How to check the result on yourselfAny calculator gives you a starting point, not a verdict. After two or three weeks, compare the estimate with reality: if your weight and wellbeing stay stable at your target, it’s right.

What to do with the numbers

A calorie target alone changes little. It becomes useful alongside three things: understanding your macro balance, a habit of logging food, and looking at weekly averages rather than single days.

That’s why in the app your target is the first step, not the result: meals go into the diary from a photo, and FoodMate Score shows what your diet is missing - most often fibre and vegetables, not “extra” calories.