TDEE Calculator

What TDEE actually means

TDEE stands for Total Daily Energy Expenditure — every calorie your body spends in twenty-four hours. It has three parts, and only one of them is exercise.

The largest is your basal metabolic rate, the energy you would burn lying still all day keeping your heart beating and your brain running. For most adults that is 60–70% of the total. Next is the thermic effect of food, roughly 10%, spent digesting what you eat — protein costs the most to process, which is one of the reasons a higher-protein diet is easier to lose weight on. Last is activity: everything from a gym session to walking to the mamak and fidgeting at your desk.

This calculator estimates the first part with the Mifflin-St Jeor equation and multiplies it by an activity factor to reach the total.

The formula

Mifflin-St Jeor is the standard, and it is deliberately simple:

• Men: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
• Women: 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

That gives BMR in calories per day. Multiply it by your activity factor:

Level	Multiplier	Looks like
Sedentary	1.2	Desk job, little deliberate movement
Light	1.375	Light exercise one to three days a week
Moderate	1.55	Moderate exercise three to five days a week
Active	1.725	Hard exercise six to seven days a week
Athlete	1.9	Physical job, or training twice a day

A 30-year-old man at 180 cm and 80 kg has a BMR of 1,780 kcal. At the moderate multiplier his TDEE is about 2,759 kcal — that is his maintenance.

Turning TDEE into a target

Maintenance is the number you eat to stay the same. To change, move off it by a percentage rather than a fixed number, because a 500 kcal cut is trivial for a 3,200 kcal athlete and brutal for a 1,600 kcal office worker.

• Fat loss: 10–20% below maintenance. Slower is not worse — it protects muscle and it is easier to keep.
• Maintenance: the number itself, useful while building the logging habit before changing anything.
• Muscle gain: 10–15% above maintenance, paired with training that justifies it.

This calculator floors every result at 1,500 kcal for men and 1,200 for women. Percentage deficits applied to a small maintenance can produce dangerous numbers, and no calculator should hand you one.

How accurate is this, honestly

An equation cannot know your body. Mifflin-St Jeor typically lands within about 10% of measured resting metabolic rate for most people, and the activity multiplier is the coarser half of the estimate — the gap between "moderate" and "active" is a judgement call worth several hundred calories.

So treat the output as a starting point, not a prescription. Eat at it for two weeks, weigh yourself under the same conditions, and adjust from what actually happens. Real data from your own body beats any formula, and after a month of logging you will have exactly that.

What to do with the number

Once you have a calorie target, split it into protein, carbs and fat with the macro calculator. Then the only hard part is logging honestly — the cooking oil, the teh tarik, the three spoons of sambal. If typing every meal into a database is what makes you quit, log by photo instead and let the app estimate the plate.