Calculators
Calorie Calculator
Estimate resting and daily energy expenditure from an adult research equation. Results are estimates, not personal eating or weight-loss targets.
An equation estimate for adults ages 19–78, the age range in the original study. It does not set an eating target and is not intended for pregnancy, breastfeeding, children or medical nutrition planning.
Enter an age from 19 to 78 and positive height and weight values to see an estimate. For imperial height, enter whole feet and inches below 12.
The formula estimates resting expenditure from weight, height, age and the male/female coefficients published in the study. It does not measure body composition or adapt to illness or medication. For a personal eating plan, consult a qualified clinician or dietitian.
Method: Mifflin et al., 1990. Further context: NIDDK Body Weight Planner.
Your inputs are calculated in your browser and are not uploaded by this tool.
Works in your browser. No account needed.
Frequently asked questions
Which equation is implemented?
The simplified Mifflin-St Jeor equation estimates resting energy expenditure in kcal/day: 10 × weight in kg + 6.25 × height in cm − 5 × age in years, then +5 for the male coefficients or −161 for the female coefficients. The original paper is linked beside the calculator. A formula estimate is different from a laboratory measurement.
Why does the calculator accept only ages 19–78?
Those were the ages in the original study, and this version keeps its age inputs within that range. That does not mean the formula is accurate for every individual in the range. It is not intended for pregnancy, breastfeeding, children or clinical nutrition planning.
What do the activity multipliers mean?
The daily estimate multiplies resting expenditure by the factor you select, from 1.2 to 1.9. These are scenario assumptions, not activity measurements or extra coefficients from the Mifflin paper. The calculator cannot determine your actual activity or energy use from a dropdown.
Why does it not provide a weight-loss target?
Subtracting a fixed number from an uncertain expenditure estimate does not establish an appropriate diet for an individual. This page therefore reports the equation and multiplier results without prescribing calorie deficits, predicting weekly weight change or setting minimum food intake.
How can I check the arithmetic?
For the male coefficients, age 30, height 175 cm and weight 70 kg give 1,648.75 kcal/day before display rounding. At a 1.55 multiplier the daily estimate is 2,555.5625 kcal/day. The screen rounds these to 1,649 and 2,556; intermediate calculations keep their precision.
Are these measurements saved?
The calculation runs in your browser. This tool does not upload or save age, height, weight or the result. Closing or reloading the page clears its form values.
About this tool
Resting energy expenditure and total daily expenditure are different quantities. This page first estimates resting expenditure from the published equation, then shows how a chosen multiplier changes it. Separating the two makes it easier to see which part comes from the inputs and which part is an assumption.
Use consistent units. Metric inputs are centimetres and kilograms. Imperial height uses whole feet plus additional inches below 12; pounds are converted to kilograms before the equation runs. A result that looks surprising is a reason to check those fields, not a reason to change what you eat.
For a comparison, hold age, height and weight constant and switch the activity factor. The result changes in direct proportion to that factor. This illustrates sensitivity to the assumption; it does not tell you which factor represents your life. Individual metabolism, body composition and medical circumstances are outside this model.
The page links the original research so the equation and study population can be checked, along with NIDDK information about a separate body-weight planning model. No clinician has assessed you through this calculator. A qualified health professional can interpret energy needs in the context of your circumstances when a personal nutrition plan is needed.