How many calories do you actually need each day?
Before you start a diet or a bulk, you need to know what calorie number you're starting from. Without it, you blindly enter "1500 kcal" into an app and then wonder why you're not losing weight, or why you feel drained.
This calculator gives you two numbers: BMR (calories at rest) and TDEE (total daily burn). Plus 5 ready targets: from aggressive cut to bulk, and the exact calorie number to hit each one.
Formula: Mifflin-St Jeor: modern medical formula from 1990. If you know your body fat percentage, the calculator switches automatically to Katch-McArdle (even more accurate, since it works off lean body mass).
How to use it
- Pick sex (male/female), the formula differs by a constant here, since on average men carry more muscle mass.
- Enter age, weight, and height. Toggle kg/lb and cm/in with a click.
- Only if you know it: fill in your body fat %. The calculator then uses the more accurate formula (Katch-McArdle).
- Pick an activity level: be honest, not aspirational. Most people overshoot. "Moderate" means really 3-5 workouts a week, not once every two weeks.
- Look at TDEE: that's your maintenance, the amount you eat to keep weight steady.
- The table below shows 5 scenarios: from cutting to bulking. Each comes with a predicted weekly weight change.
- Tip: eat to plan for 2 weeks. Weight not moving? Drop 100-200 kcal. Falling too fast (>1% body weight per week)? Add some back.
When this is useful
Six typical reasons someone reaches for a BMR/TDEE calculator:
- Starting a diet, no clue where to begin: the internet shouts "1200 kcal!", a friend says "1800!", an app says "1450!". You enter your data and get a concrete number for you: not for the average woman.
- A doctor or coach asks for your TDEE: at most dietitian appointments, the first question is "what's your maintenance?". Better to know before you walk in.
- Checking whether an app got it wrong: Cronometer, MyFitnessPal, Yazio all have built-in calculators. Sometimes they give odd results (often too low, because they use the older Harris-Benedict formula). This is a second, independent source of truth.
- Not losing weight despite a "deficit": you eat "1500 kcal" by your own count, the scale won't budge. Real TDEE is 1700 kcal, so your "1500 kcal" plus the things you don't count (oil, sauces, wine) lands right at maintenance. There is no deficit, that's why nothing's happening.
- Planning a bulk after cutting: you've cut, now you want to add muscle without piling on fat. Enter the new weight, the calculator shows your new TDEE (lower than before, your body adapts). Pick "lean bulk" (TDEE +250 kcal) and run it.
- Checking if 1200 kcal is too low: if your BMR is 1400 kcal, eating 1200 kcal is below what your heart and brain need to function. Over time the body slows your metabolism. This calculator shows you the safety floor.
Questions and answers
BMR = how many calories your body burns lying in bed for 24 hours, doing nothing. The basics of being alive, heart beating, lungs breathing, brain working, food digesting. TDEE = BMR + everything else you do in a day: walking, working, training, talking, even digesting your last meal (yes, digestion costs calories too). TDEE is always higher than BMR, usually 1.2× to 1.9× depending on activity.