The short answer
Your daily calorie needs are your total daily energy expenditure (TDEE): the calories your body burns at rest, multiplied by an activity factor. Enter your age, sex, height, weight and activity level to estimate maintenance calories, then see cautious calorie targets for losing, maintaining or gaining weight.
Formulas and sources are named on this page. How we calculate.
How this is calculated
The calculator works in three steps: estimate resting energy, scale it for activity, then add or remove calories for your goal.
Step 1 (BMR, Mifflin–St Jeor):
Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Step 2 (TDEE): BMR × activity factor
Step 3 (target): TDEE + (kg per week × 7,700 ÷ 7)
Worked example
A 35-year-old man, 180 cm tall, weighing 85 kg, who exercises 3 to 5 days a week (factor 1.55) and wants to lose about 0.5 kg a week.
- BMR = 10 × 85 + 6.25 × 180 − 5 × 35 + 5 = 850 + 1,125 − 175 + 5 = 1,805 kcal
- TDEE = 1,805 × 1.55 = about 2,800 kcal
- Daily change for 0.5 kg a week = 0.5 × 7,700 ÷ 7 = 550 kcal, so the target is 2,798 − 550 = about 2,250 kcal
- Safety check: 2,250 is above the 1,500 kcal floor and less than 25% below maintenance, so no limit applies.
Why the 7,700 kcal figure is only a guide
About 7,700 kcal is a common estimate of the energy in a kilogram of body-weight change (the older 3,500 kcal per pound rule is the same idea). Research by Hall and colleagues shows that weight change slows as the body adapts, so simple arithmetic tends to overstate long-term loss. The NIDDK Body Weight Planner models this more closely.
Safety rules built into the targets
- Targets are never below 1,200 kcal (women) or 1,500 kcal (men). Diets of 800 kcal a day or less are classed as very low-calorie diets and need medical supervision.
- A weight-loss target is never more than 25% below maintenance, and rates are capped at about 1 kg (2 lb) a week. The CDC describes a gradual pace of about 1 to 2 pounds a week as more likely to be sustained.
- If BMI is below 18.5, weight-loss targets are not shown.
The floors and the 25% cap are our own conservative editorial rules rather than a clinical protocol.
Activity levels and multipliers
Activity factors used to turn BMR into TDEE| Activity level | Factor | Typical week |
|---|
| Sedentary | 1.2 | Little or no exercise, desk job |
| Lightly active | 1.375 | Light exercise 1–3 days a week |
| Moderately active | 1.55 | Moderate exercise 3–5 days a week |
| Very active | 1.725 | Hard exercise 6–7 days a week |
| Extra active | 1.9 | Very hard exercise plus a physical job or two sessions a day |
These multipliers are widely used estimates. The FAO/WHO/UNU framework expresses the same idea as a physical activity level (PAL), and real activity varies a lot from person to person.
Frequently asked questions
What is TDEE?
TDEE stands for total daily energy expenditure: all the calories you burn in a day, including resting metabolism, movement, exercise and digesting food. Eating around your TDEE keeps weight roughly stable; eating less or more tends to lower or raise it over time.
How accurate is a calorie calculator?
It gives an estimate, not a measurement. People of the same age, size and sex can differ in how many calories they burn. Use the result as a starting point and watch how your weight changes over several weeks.
How many calories should I eat to lose weight?
A common approach is to eat somewhat below your maintenance calories. This calculator applies the deficit for the rate you choose but stops at safe minimums. The CDC describes about 1 to 2 pounds (0.5 to 1 kg) a week as a gradual pace. A doctor or dietitian can tailor a plan to you.
Why does the calculator show a higher target than I chose?
Because the rate you picked would have taken your intake below 1,200 kcal (women), 1,500 kcal (men) or more than 25% below maintenance. The tool raises the target to the safe limit and tells you when it has done so.
Which activity level should I choose?
Pick the level that matches a typical week, including your job. Most people overestimate their activity, so if you are unsure choose the lower option and adjust after a few weeks.
Can teenagers, pregnant women or people with medical conditions use it?
No. The formulas are designed for healthy adults. Energy needs differ in growth, pregnancy, breastfeeding and some medical conditions, so speak to a doctor or registered dietitian instead.
Disclaimer and editorial note
For information only, not medical advice. This calculator gives general estimates from the numbers you enter. It cannot diagnose, treat or prevent any condition and does not replace advice from a doctor, midwife, registered dietitian or other qualified professional who knows your history.
Written and maintained by the HealthFitnessHQ editorial team. We name the source of every formula and category used, and we review each calculator when guidance changes. Read how we work in our editorial policy and methodology.