Calorie calculator: daily calories, BMR, TDEE and macros

How the calorie calculator works

Basal metabolic rate (BMR) from the Mifflin-St Jeor equation. Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161. Men: the same with +5 instead of −161.
Total daily energy expenditure (TDEE): BMR times an activity factor between 1.2 and 1.9 (see the table).
Goal: 85% of TDEE to lose fat (about a 15% deficit), 100% to maintain, 112% to build muscle.
Macros: protein at 1.8 g per kg of body weight (2.0 g when building muscle), fat at 28% of calories, carbs for the rest. The Fit Chef app uses the same numbers.

An example: a 30-year-old woman, 165 cm and 60 kg, has a BMR of 1,320 kcal. Training 3-5 times a week (× 1.55) her TDEE is about 2,050 kcal, so her fat-loss target is 1,740 kcal with 108 g of protein.

Activity factors

Activity	Factor
Sedentary: little or no exercise	1.2
Lightly active: 1-3 workouts a week	1.375
Moderately active: 3-5 workouts a week	1.55
Very active: 6-7 workouts a week	1.725
Extra active: physical job plus daily training	1.9

Most people overestimate how active they are. With a desk job and three workouts a week, start at lightly active and adjust from your weight trend.

Calorie deficit: how much less to eat

A 15% deficit is 300-500 kcal a day for most people, roughly 0.5% of body weight lost per week. A bigger deficit is faster but harder to stick to and costs more muscle. Don’t eat below your BMR for long, and without professional support don’t go below 1,200 kcal as a woman or 1,500 kcal as a man. More in how to set a calorie deficit.

Macros: protein, carbs and fat

Protein matters most while you lose fat: it helps you keep muscle and keeps you fuller. Keep fat above roughly 20-25% of calories over the long run, since hormones depend on it. Carbs fuel training and take the remaining calories. To fine-tune protein, use the protein calculator.

Why it is an estimate

Mifflin-St Jeor predicts measured resting metabolism within 10% for most healthy adults, but individuals can be further off. Start with the calculated number, weigh yourself several times a week at the same time of day, and after 2-3 weeks adjust by 100-200 kcal based on the weekly average.

Plan ahead instead of counting

Most calorie counter apps ask you to log what you already ate. The Fit Chef works the other way round: set your calorie target and the app plans your week from its recipes, macros included. Log with one tap after eating, and the shopping list builds itself.

Frequently asked questions

How many calories do I need a day?

It depends on your size, age and activity. The Dietary Guidelines for Americans estimate about 1,600-2,400 kcal a day for adult women and 2,000-3,000 kcal for men. The calculator above gives your own number.

What is BMR?

Basal metabolic rate is the energy your body uses in a day at complete rest: breathing, circulation, keeping warm. It is the largest part of your daily energy use.

What is the difference between BMR and TDEE?

BMR is energy at rest; TDEE is your total for the day: BMR plus all movement, exercise and digestion. TDEE is BMR multiplied by an activity factor.

How big should my calorie deficit be?

For most people 15-20% is sustainable, about 300-500 kcal a day. Don’t eat below your BMR for long, and without professional support stay above 1,200 kcal (women) or 1,500 kcal (men).

How much protein do I need when losing fat?

With regular training, about 1.8-2.4 g per kg of body weight. The protein calculator works out yours.

Why is the app’s number different?

On day one the app estimates from your weight only, so you can start quickly. This calculator also uses your age, height and activity; you can enter the target you get here in the app’s settings.

Sources

Last updated: October 25, 2026