Calorie & BMI calculator
From your sex, age, height, weight and activity level, get your BMI (with the healthy-weight range for your height), BMR, maintenance calories (TDEE), a daily calorie target for your goal, and a protein/carb/fat macro split. Metric or imperial, saved on your device, export a PNG. Estimates only — not medical advice.
Open Calorie & BMI calculator →What is the Calorie & BMI calculator?
A private health calculator that turns your sex, age, height, weight and activity level into your BMI (with the healthy-weight range for your height), your BMR, your maintenance calories (TDEE), a daily calorie target for your goal, and a protein/carb/fat macro split. It runs entirely in your browser, saves your details on your device, and never sends anything anywhere. These are estimates only, not medical advice.
How to use Calorie & BMI calculator
- Pick metric or imperial — Use the Metric / Imperial toggle so you can enter your height and weight in centimetres and kilograms, or feet/inches and pounds.
- Enter your details — Fill in your sex, age, height and weight. The sex setting is used by the BMR formula.
- Choose activity, goal and macro split — Pick how active you are, whether you want to lose, maintain or gain weight, and a macro split (balanced, low-carb or high-protein).
- Read your results — Your BMI, healthy-weight range, BMR, maintenance calories, daily calorie target and macro breakdown update live as you type.
- Save a copy — Use the PNG summary action in the header to download your results as an image for your own records.
Frequently asked questions
Which formula does it use?
It estimates your BMR with the Mifflin-St Jeor equation, then multiplies by your activity level to get your maintenance calories (TDEE) and adjusts for your goal.
Is BMI a reliable measure?
BMI is a rough screening number, not a diagnosis. It doesn't account for muscle, pregnancy or body composition, so treat the healthy-weight range as a guide rather than a verdict.
Are my details uploaded anywhere?
No. Everything is calculated in your browser and saved only on your device, so your figures never leave your computer.
How is the calorie target worked out?
It adds a daily surplus or deficit to your maintenance calories based on your goal — for example about 500 kcal below maintenance to lose roughly half a kilo a week.
Can I rely on this for medical decisions?
No. These are starting-point estimates only. For medical or dietary decisions, speak to a doctor or dietitian.
Tips
- Be honest about your activity level — overestimating it inflates your calorie target.
- Treat the macro grams as a daily target, not a hard rule for every meal.
- Re-check your numbers every few weeks as your weight changes, since BMR shifts with it.
- Download the PNG summary if you want to track changes over time.