How the daily calorie estimate works
First, the Mifflin–St Jeor equation estimates BMR from weight in kilograms, height in centimetres and age in years:
Male equation: BMR = (10 × weight) + (6.25 × height) − (5 × age) + 5
Female equation: BMR = (10 × weight) + (6.25 × height) − (5 × age) − 161
The estimated BMR is then multiplied by the activity factor selected above. The factors are simplified assumptions, not precise measurements of daily movement or energy expenditure.
BMR and TDEE: what is the difference?
BMR estimates energy used at rest. Total daily energy expenditure also includes physical activity and other energy uses. Because both the equation and activity factor are estimates, the result can differ from a person's actual energy needs.
Frequently asked questions
Is this the number of calories I should eat?
Not necessarily. The calculator estimates energy expenditure; it does not prescribe an intake. Individual needs depend on health, growth, activity, circumstances and other factors.
How accurate is the daily calorie estimate?
It is a formula-based estimate. The accuracy depends on the equation's fit to an individual and how well the activity multiplier represents their usual routine.
Which activity level should I choose?
Choose the closest broad description of your usual activity, while remembering that the categories are simplified. If unsure, compare results across adjacent levels rather than treating one number as exact.
Can teenagers use this calculator?
No. This page is intended for adults aged 18 and over. Children and teens have different energy and growth considerations and need age-appropriate guidance.
Can I use this for a medical diet?
No. This general tool does not account for every health condition or clinical nutrition need. Seek guidance from a qualified healthcare professional or registered dietitian for individualized advice.
DietDelta provides general educational information. It does not diagnose conditions or provide individualized medical nutrition therapy.
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