Calorie Calculator
Your maintenance calories, the target that goes with your goal, and the macros to hit it. Nothing to sign up for, and nothing you type leaves this page.
Eat this much per day
calories
BMR
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Maintenance
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Adjustment
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Macros
Protein
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Carbs
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Fat
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Knowing the number is the easy part
Hitting it every day is the work. Food Cal AI logs a meal from a photo, keeps the running total, and remembers what you ate yesterday — none of which a calculator can do.
How the number is worked out
Your BMR comes from the Mifflin-St Jeor equation, which has been the most accurate of the common formulas since it replaced Harris-Benedict in the 1990s. It takes weight, height, age and sex, and returns the calories you would burn lying still all day.
That gets multiplied by an activity factor — 1.2 for a sedentary week up to 1.9 for someone training twice a day — to give TDEE, the amount that keeps your weight where it is. Your goal is then a straight adjustment: about 550 calories a day below maintenance to lose half a kilo a week, or above it to gain.
The mistake almost everyone makes
Overestimating activity. “Moderately active” means genuinely training three to five times a week, every week — not a good intention and two sessions. The difference between sedentary and moderately active for the same person is often 500 calories a day, which is the entire deficit. If your weight has not moved in three weeks, this is the first thing to change.
Why protein is set per kilogram
Percentage-based macro splits fall apart at the extremes: 30% protein is far too little for a small person in a deep deficit and more than anyone needs at 3,500 calories. Setting protein against bodyweight — 1.6 g/kg for a balanced split, 2.2 g/kg for high protein — tracks what the research actually supports for keeping muscle while losing fat. Fat is then set as a share of calories, with carbs taking the remainder.
What to do with the number
Eat at it for two to three weeks and weigh yourself at the same time each day, then average each week. If the average has not moved and you want it to, take 150 calories off and repeat. The calculator gives you a starting point; the scale over time is what tells you your real maintenance level. That is also why a food log beats recalculating — the equation cannot see what you actually ate.
Questions
What is TDEE, and how is it different from BMR?
BMR is what your body burns doing nothing at all — breathing, pumping blood, keeping warm. TDEE is BMR plus everything else: walking, working, training, even digesting. BMR is the floor; TDEE is what you actually need to eat to stay the same weight.
How accurate is this?
Within about 10% for most people, which is as good as any equation gets without a metabolic cart. Two people with identical numbers can differ by a few hundred calories a day. Treat the result as a starting point: eat at it for two or three weeks, track your weight, and adjust by 100–200 calories based on what actually happened. The scale is the real calculator.
Which activity level should I pick?
Almost certainly a lower one than you think. Activity level is about your whole week, not your best day — a desk job plus three gym sessions is “lightly active”, not “very active”. Choosing one level too high is the single most common reason a calculated deficit fails to produce any weight loss.
Why does 0.5 kg a week mean 550 calories a day?
A kilogram of body fat holds roughly 7,700 calories. Half of that spread over seven days is about 550 a day. It is a planning figure rather than a law of physics — early weight change is mostly water, and your body burns a little less as you get lighter — but it is close enough to build a week around.
Do the macros matter, or just the calories?
Calories decide the weight. Macros decide what you lose and how you feel doing it. Protein is the one that matters most in a deficit — it protects muscle and keeps you full — which is why it is set per kilogram of bodyweight here rather than as a percentage. Fat has a floor for hormone health, and carbs take whatever is left.
Is a very low calorie target dangerous?
It can be, which is why the result stops at 1,500 for men and 1,200 for women. Below that it is hard to get enough protein and micronutrients, and adherence collapses. If a faster result matters, add activity rather than cutting further, and talk to a doctor before going lower.
