What is a calorie calculator?
A calorie calculator estimates an adult's daily energy needs from age, body measurements, a formula setting and an activity level. It shows an estimated basal metabolic rate (BMR), which is the energy used for basic body functions at rest, and an estimated maintenance-calorie figure after applying an activity multiplier. The result can be a starting point for understanding general energy needs.
This calculator runs entirely in your browser. Your age, measurements and selections are not uploaded, stored or shared. It supports metric and imperial measurements, then converts the values internally for the calculation.
How to use this calorie calculator
- Choose metric or imperial measurements.
- Select the formula setting that applies to you and enter your adult age.
- Enter your weight and height.
- Choose the activity level that best reflects your usual routine.
- Review the estimated BMR and daily maintenance calories.
The activity descriptions are broad estimates. Consider both structured exercise and physically demanding work when choosing a level. The displayed maintenance number estimates the calories needed to maintain weight under the assumptions entered; it is not a prescribed calorie target.
How the estimate is calculated
The calculator uses the Mifflin–St Jeor BMR equation, which uses weight in kilograms, height in centimetres, age and a sex-specific coefficient. It then multiplies the BMR by a standard activity factor to estimate total daily energy expenditure (TDEE). The formula setting offers male and female coefficients because that is how the equation was developed.
The same person can receive different estimates when their reported activity changes. The calculation cannot directly measure metabolism, body composition, daily movement, medications, health conditions, sleep, stress, recovery or changes in training. Those factors can all make actual energy needs higher or lower than a formula-based estimate.
Important health limits
This tool is for adults aged 18 and older and is not intended for pregnancy, breastfeeding, an eating disorder, illness or a personalized treatment plan. Calorie needs are individual and may vary from standard reference values. If you have a medical condition, a history of disordered eating, unexplained weight change, or need nutrition support for sport or treatment, speak with a qualified clinician or registered dietitian. Use this result for general planning only, and avoid making abrupt dietary changes solely from an online estimate.