How are calorie needs estimated?
First, the Mifflin–St Jeor equation estimates resting energy expenditure. The selected activity factor is then applied to estimate daily maintenance calories.
Male: 10 × weight + 6.25 × height − 5 × age + 5
Female: 10 × weight + 6.25 × height − 5 × age − 161
This is not a direct measurement. Methods such as indirect calorimetry can assess individual energy expenditure more directly than predictive equations.
Weight-loss / weight-gain goals: This calculator does not automatically prescribe a “−500 kcal” deficit or “+300 kcal” surplus. Weight-change plans should consider starting weight, health status and eating behavior.
Frequently Asked Questions
How are calorie needs calculated?
The Mifflin–St Jeor equation first estimates resting energy expenditure. The selected activity factor then produces an approximate daily maintenance-calorie estimate.
Why is the result not an exact number?
The equations do not directly measure metabolism or daily movement. Body composition, actual activity and individual metabolic differences can change real energy needs, so the result is an estimate.
How many calories should I eat to lose or gain weight?
This calculator does not prescribe a personal calorie target for weight change. Goals should be considered with health status, starting weight, eating pattern and other individual factors.
How should I choose an activity level?
Consider normal daily movement and regular exercise together. Because activity factors are approximate, choosing a level above your routine can overestimate maintenance calories.
Can this calculator replace a dietitian or doctor?
No. The result is a general planning estimate and does not replace individualized medical or nutrition advice.