Calorie Calculator

Estimate daily calorie needs based on your activity level.

Results

Maintain Weight

0 cal

Lose 0.5 kg/week

0 cal

Gain 0.5 kg/week

0 cal

Overview

Daily calorie needs are not a one-size-fits-all number. They depend on age, sex, body size, hormones, and how much a person actually moves during the day. This calculator uses the Mifflin-St Jeor equation, which is the formula most registered dietitians and the Academy of Nutrition and Dietetics currently recommend for estimating Basal Metabolic Rate (BMR) in healthy adults. The BMR is the energy the body burns at complete rest, just to keep the heart, brain, and lungs running. On top of that, the calculator multiplies by an activity factor (1.2 to 1.9) to estimate Total Daily Energy Expenditure (TDEE), often called maintenance calories.

TDEE is the right number to use as a starting point. It is the rough average calories needed to keep weight stable over weeks and months. Real daily intake can swing above and below that line, but the weekly average tends to drive weight change. A single day at 2,200 kcal versus 1,800 kcal usually does very little; doing that for months does. The two numbers shown below the maintenance line, for losing and gaining weight, are simply that baseline minus or plus 500 kcal, which is the most common starting prescription for a slow, sustainable change.

A note on units: the form is set to metric by default (centimeters and kilograms), which keeps the math close to the underlying formula. If you only know your height in inches or your weight in pounds, the quickest conversion is 1 inch = 2.54 cm and 1 kg = 2.205 lb. The five activity labels map to industry-standard multipliers, but they are honest descriptions of an average week, not a wish list. Most people overestimate how much they exercise and underestimate how much they sit.

This tool is a planning aid, not a medical device. People with thyroid conditions, very low body fat, pregnancy, intense training blocks, or chronic illness often need numbers outside the standard range. For any personalized plan, especially one involving weight loss for a child, an athlete, or someone with a medical condition, a registered dietitian or physician is the right next step. Treat the result as a reasonable starting point, then track actual weight and hunger over 2 to 4 weeks and adjust from there.

How to use

  1. Pick the biological sex used for the formula (the BMR equation differs slightly for males and females).
  2. Enter age in years, height in centimeters, and current weight in kilograms.
  3. Choose the activity level that best matches a typical week, not the best week of the year.
  4. Read the TDEE (maintenance) number, then use the lose and gain values as reference targets for cutting or bulking.

Formula

Mifflin-St Jeor BMR: men = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; women = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. TDEE = BMR × activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 active, 1.9 very active).

Interpreting your results

The maintenance number is the daily calories to keep weight stable. To lose weight, subtract roughly 500 kcal per day for about 0.5 kg (1 lb) of loss per week; to gain weight, add 500 kcal. Avoid going below the BMR for long periods. Very large deficits (over 1,000 kcal/day) usually cause muscle loss, fatigue, and metabolic slowdown. Slow changes in the 250-500 kcal range are easier to stick with and protect lean mass.

Frequently asked questions

How accurate is a calorie calculator?
Mifflin-St Jeor estimates BMR within about 10 percent for most healthy adults. Real needs vary with genetics, sleep, stress, muscle mass, and hormones, so treat the result as a baseline. Weigh yourself weekly and adjust intake if the trend does not match the goal.
How much weight can I lose in a week?
A safe, sustainable rate is about 0.5 to 1 kg (1 to 2 lb) per week, which lines up with a 500 to 750 kcal daily deficit. Faster loss is possible early on due to water and glycogen changes, but ongoing loss beyond that usually costs muscle mass.
Which activity level should I pick if I sit most of the day?
Use Sedentary (1.2) if there is little to no structured exercise and a desk job. A short daily walk plus a couple of gym sessions per week is closer to Light (1.375). It is better to under-pick slightly and adjust based on real weight trends than to overestimate and stall.
Should I eat back calories burned exercising?
For most people, the activity factor already includes normal daily movement, so additional exercise calories do not need to be fully replaced. Eating back 30 to 50 percent of what a fitness tracker reports is a reasonable middle ground for active individuals.

Related calculators