How This Calorie Calculator Works
This calculator estimates your daily calorie needs using the Mifflin-St Jeor equation, one of the most accurate and widely used formulas for estimating Basal Metabolic Rate (BMR), then adjusts it based on your activity level to find your Total Daily Energy Expenditure (TDEE).
The Mifflin-St Jeor Formula
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Your BMR is then multiplied by an activity factor to estimate your total daily calorie burn (TDEE).
Using These Numbers for Weight Goals
To lose weight, most people create a moderate calorie deficit (around 500 calories/day below maintenance leads to roughly 0.5kg/1lb of weight loss per week). To gain weight, a similar surplus is used. Very large deficits or surpluses aren't usually sustainable or healthy — gradual changes tend to work better long-term.
Why Activity Level Matters
Your activity multiplier has a big impact on your total calorie needs. Someone with a desk job and no exercise needs meaningfully fewer calories than someone doing intense daily training, even with the same age, height, and weight.
Frequently Asked Questions
Is this calculator accurate for everyone?
It provides a solid estimate for most people, but individual metabolism varies due to genetics, muscle mass, and health conditions. Use it as a starting point and adjust based on your real-world results over a few weeks.
What's a safe calorie deficit for weight loss?
A deficit of 500 calories/day (roughly 0.5kg or 1lb loss per week) is commonly recommended as sustainable. Very low-calorie diets should only be done under medical supervision.
Does this account for pregnancy or medical conditions?
No, this is a general estimate for healthy adults. If you're pregnant, breastfeeding, or managing a medical condition, consult a doctor or registered dietitian for personalized calorie guidance.