Everyday tool
BMI and Calorie Calculator
Calculate your BMI, BMR with the Mifflin-St Jeor equation, daily calories (TDEE) and protein, carb and fat targets, in metric or imperial units.
Free, no sign-up. Runs in your browser; nothing is uploaded.
For general information only, not medical advice. BMI ignores muscle, age and body shape. Talk to a doctor or dietitian before changing your diet, especially if you are pregnant, under 18 or have a health condition.
About you
Body mass index
A BMI of 18.5 to 24.9 at your height is 52.2 kg to 70.3 kg.
Daily calories
BMR uses the Mifflin-St Jeor equation; TDEE is BMR multiplied by your activity factor. Targets never drop below 1200 kcal.
Daily macros
Protein about 1.6 g per kg of body weight, fat 25% of calories, carbohydrates fill the rest.
How to use the bmi and calorie calculator
Understand your numbers
This calculator combines three useful measurements: BMI, your basal metabolic rate (BMR) and your daily calorie and macro targets.
Enter your details
Pick metric (centimetres and kilograms) or imperial (feet, inches and pounds), choose the sex used by the formula, and enter your age. Select your usual activity level and a goal: lose gently, maintain or build. Results appear instantly.
What you get
- BMI with a colour scale and a category: underweight below 18.5, healthy 18.5 to 24.9, overweight 25 to 29.9 and obese range from 30. You also see the weight range that corresponds to a healthy BMI at your height.
- BMR is the energy your body uses at rest, calculated with the Mifflin-St Jeor equation.
- TDEE multiplies BMR by an activity factor to estimate daily maintenance calories.
- Target calories apply your goal: about 500 fewer calories to lose weight at a gentle pace, or 300 more to build. The target never falls below 1,200 kcal for women or 1,500 kcal for men.
- Macros give grams of protein, carbohydrate and fat that add up to your target.
Using the results sensibly
- Treat every number as an estimate. Individual metabolism varies by 10% or more.
- Track your weight and energy for two to three weeks, then adjust the calories up or down.
- Aim for gradual change. A loss of 0.25 to 0.5 kg a week is easier to sustain.
- Pair food changes with strength training and sleep.
Important
This tool is for general information and is not medical advice. BMI is not suitable for children, pregnant women or competitive athletes. If you have a health condition, take medication or are unsure, ask a healthcare professional. Your details are processed only in your browser.
Frequently asked questions
Is BMI accurate?
BMI is a quick screening number based on height and weight only. It does not separate muscle from fat, so athletes can read high and older adults can read normal with low muscle. Use it as a rough guide, not a diagnosis.
Which equation is used for BMR?
The Mifflin-St Jeor equation: 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5 for men or - 161 for women. It is widely recommended as one of the more accurate estimates for healthy adults.
What is TDEE?
Total daily energy expenditure is your BMR multiplied by an activity factor from 1.2 (desk job) to 1.9 (very active). It estimates the calories you burn in a day and is the maintenance level.
How are the macros chosen?
Protein is about 1.6 to 1.8 grams per kilogram, fat is 25% of calories, and carbohydrates fill the rest. These are common starting points; a dietitian can tailor them to your needs.
Is this medical advice?
No. It is general information. Speak to a doctor or registered dietitian before changing your diet, especially if you are under 18, pregnant, elderly or have a medical condition.