How the calorie calculator works
First it estimates your basal metabolic rate (BMR) — the energy your body uses at rest — with the Mifflin-St Jeor equation. Then it multiplies BMR by an activity factor to get your total daily energy expenditure (TDEE), the calories that keep your weight steady.
Calories to lose weight
Body fat holds about 7,700 kcal per kilogram (about 3,500 kcal per pound). So a daily deficit of roughly 550 kcal leads to about 0.5 kg a week, and 500 kcal to about 1 lb a week. Real weight loss slows over time as your body adapts, so treat these as starting points. Read more in our calorie deficit guide.
Choosing your activity level
| Level | Factor | Looks like |
|---|---|---|
| Sedentary | 1.2 | Office job, under 5,000 steps |
| Light | 1.375 | Walks or workouts 1–3 days a week |
| Moderate | 1.55 | Workouts 3–5 days a week |
| Very active | 1.725 | Hard training most days |
| Extra active | 1.9 | Manual job plus training |
Australia and New Zealand food labels use kilojoules: 1 kcal = 4.184 kJ. The calculator shows both.
Calorie Calculator FAQs
How many calories should I eat a day?
It depends on your size, age, sex and activity. US Dietary Guidelines estimate about 1,600–2,400 kcal a day for adult women and 2,000–3,000 kcal for men. Enter your details above for a personal estimate.
How many calories to lose 1 kg a week?
About 1,100 kcal a day below maintenance, which is a lot for most people. A slower 0.5 kg a week (about 550 kcal deficit) is easier to keep up.
What is the Mifflin-St Jeor equation?
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or −161 for women. It is considered one of the most accurate everyday BMR formulas.
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest. TDEE adds daily movement and exercise, so it is the number to base your eating on.