Calorie Calculator
Estimate maintenance calories using the Mifflin–St Jeor equation.
Last updated: July 2026
Estimated maintenance calories
0 kcal/day
On this page
Quick summary: Estimate daily calorie needs. Enter the requested values, calculate, review the result, and compare more than one realistic scenario before making a decision.
Read the complete guide
What this calculator does
The Calorie Calculator estimates daily energy needs from personal characteristics and activity level. It is mainly useful for understanding approximately how many calories may maintain current body weight before applying a controlled calorie surplus or deficit.
How to use the calculator step by step
Enter the requested age, sex, height, weight, and activity level using the units shown. Choose an activity category that reflects your normal weekly routine rather than your most active day. Calculate the estimate, then use it as a starting point and compare it with real changes in body weight over several weeks.
How the calculation works
Daily calorie estimates typically begin with basal metabolic rate and multiply it by an activity factor. BMR represents energy used at rest, while the activity multiplier estimates movement, exercise, and daily tasks. The result is an estimate of total daily energy expenditure rather than a directly measured metabolic rate.
Worked example and scenario testing
If an estimated BMR is 1,600 calories per day and the selected activity multiplier is 1.55, estimated maintenance energy is about 2,480 calories per day. A person's actual requirement may be higher or lower, so observed weight trends are important when adjusting intake.
How to interpret your result
The result represents an approximate maintenance intake, not a mandatory daily target. Consistently eating above maintenance tends to support weight gain, while eating below maintenance tends to support weight loss, but the rate differs between individuals.
Accuracy, assumptions, and limitations
Energy equations cannot directly measure metabolism, body composition, adaptive changes, pregnancy needs, illness, medication effects, or highly unusual training loads. Short-term body-weight changes also reflect water and glycogen, not only body fat.
Common mistakes to avoid
Common mistakes include selecting an activity level that is too high, mixing pounds with kilograms, treating the estimate as exact, or making a large diet change based on only a few days of scale readings.
Privacy and browser-based calculations
The calculator only needs the health-related values shown in the form. Avoid entering names, medical record numbers, addresses, or other identifying information.