Work out how many calories you need per day with the Mifflin-St Jeor or Harris-Benedict formula: basal metabolic rate, maintenance calories, a target for your goal and the macro breakdown. Free, no sign-up, and nothing you type is stored.
Your target has been held at the generally recommended minimum intake (1,200 kcal for women, 1,500 for men). Going below it, or eating at a level this close to your estimated expenditure, should be supervised by a healthcare professional.
Values recalculate instantly as you type. Nothing is sent or stored — the math runs in your browser.
The calculator first estimates your basal metabolic rate (the calories your body burns at complete rest) and multiplies it by a factor for your activity level to get your maintenance calories. Your goal then applies the deficit or surplus of the pace you chose on top of that number.
Mifflin-St Jeor (1990, the most accurate for the general population):
Men: (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
Women: (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Revised Harris-Benedict (Roza & Shizgal, 1984):
Men: 88.362 + (13.397 × weight kg) + (4.799 × height cm) − (5.677 × age)
Women: 447.593 + (9.247 × weight kg) + (3.098 × height cm) − (4.330 × age)
The macro breakdown uses standard acceptable macronutrient distribution ranges: more protein when losing fat (30%), more carbohydrate when gaining (50%), always within AMDR. The estimated weekly pace derives from the approximate equivalence of 3,500 kcal per pound of body fat.
Every formula is a statistical estimate: your real number varies with body composition, genetics and metabolic adaptation. It is not valid during pregnancy or breastfeeding, for people under 18, for elite athletes or with metabolic conditions — in those cases the reference should come from a healthcare professional. The way to refine the number is to log what you eat for two or three weeks and compare it with how your weight actually moves.
Enter your sex, age, height, weight and activity level in the calculator. It first estimates your basal metabolic rate with the Mifflin-St Jeor or Harris-Benedict formula, then multiplies it by your activity factor to get your maintenance calories. Your goal — maintain, lose or gain — is applied on top of that number.
Weight is only one of the variables: two people with the same weight but different height, age, sex or activity level need different calories. That is why the calculator asks for all five inputs instead of applying a fixed rule per pound. As a reference, the maintenance result is the intake at which your current weight tends to stabilize.
It depends on your expenditure. If your maintenance is 2,000 kcal, eating 1,500 creates a deficit of about 500 kcal per day — roughly 1 lb of fat per week if sustained. If your maintenance is 1,600, the deficit is minimal. Below 1,200 kcal (women) or 1,500 kcal (men), professional supervision is recommended.
This calculator estimates how many calories you need; knowing how many you eat requires logging each meal. PlateLens does that from a photo of your plate, a text or voice description, or a barcode scan, and shows the calories and macros of every meal against your daily target.
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The calculator gives you the target; PlateLens counts what you actually eat each day from a photo, text, voice or barcode, and compares it with your goal.
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