Stax

Calorie Calculator

Calculate BMR, TDEE, and daily calorie needs.

Understanding your calorie needs

Calories are a measure of energy. Your body needs a certain amount each day to maintain weight — this is your TDEE. Eat less and you lose weight; eat more and you gain. The question is: how much is "just right" for your body?

The Mifflin-St Jeor equation, developed in 1990, is validated across multiple studies and is recommended by the Academy of Nutrition and Dietetics as the most accurate predictive equation for most adults.

Activity levels explained

  • Sedentary — desk job, little movement outside work
  • Lightly active — walking, light gym 1–3 days/week
  • Moderately active — gym 3–5 days/week or physical job
  • Very active — hard training 6–7 days/week
  • Extra active — athlete or heavy manual labor daily

Most people overestimate their activity level. If unsure, start with "Lightly active" and adjust based on real-world results over 2–3 weeks.

Macronutrients

The macronutrient split shows how to distribute your calories. The 40/30/30 ratio shown is a general starting point. Athletes may need more protein (35–40%). Low-carb dieters may prefer 20/30/50 (carb/protein/fat). The best ratio is one you can sustain consistently.

Frequently asked questions

What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep organs functioning. It accounts for breathing, circulation, cell production, and temperature regulation. It's the minimum calorie intake needed to sustain life.
What is TDEE?
TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor. It represents the total calories your body burns in a day including all physical activity. Eating at TDEE maintains your current weight.
What equation does this use?
This calculator uses the Mifflin-St Jeor equation, considered the most accurate for most people. For men: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5. For women: same formula but −161 instead of +5.
How many calories should I eat to lose weight?
A deficit of 500 kcal/day leads to roughly 0.5 kg loss per week. A deficit of 1000 kcal/day leads to roughly 1 kg/week. Going below 1200 kcal (women) or 1500 kcal (men) is not recommended without medical supervision.
What is the 40/30/30 macro split?
The 40/30/30 split (carbs/protein/fat) is a popular balanced macronutrient ratio. Carbs provide 4 kcal/g, protein provides 4 kcal/g, and fat provides 9 kcal/g. This ratio supports both performance and body composition goals for most active people.

Related tools