About Calorie Calculator

Calculate daily calorie needs (TDEE) based on age, weight, height, activity level. Part of the DevTools Surf developer suite. Browse more tools in the Calculators collection.

Use Cases

• Calculate daily calorie target for a specific weight loss rate
• Determine maintenance calories after reaching goal weight
• Estimate TDEE for an athlete with varying training days
• Set calorie targets for meal planning applications

Tips

• Select your activity level carefully — sedentary vs lightly active is the most common mistake and causes the biggest error in TDEE estimates
• The Mifflin-St Jeor equation (1990) is used by default — it is the most accurate for general use; toggle to Harris-Benedict for comparison
• Use the goal adjustment to find the calorie target for specific weight loss or gain rates (1 lb/week requires a 500 kcal/day deficit)

Fun Facts

• A calorie (kilocalorie) is the amount of energy needed to raise 1 kilogram of water by 1 degree Celsius. The food calorie is actually a kilocalorie (1,000 calories by physics definition) — a naming confusion that has persisted for over 150 years.
• The concept of counting food calories was pioneered by Wilbur Atwater in the 1890s. He built a device called a respiration calorimeter to measure how much heat the human body generates — the origin of all modern calorie databases.
• The US FDA mandates calorie labeling on restaurant menus with more than 20 locations — a rule that took effect in 2018. Studies show calorie labels reduce ordered calories by an average of only 60 kcal per meal, far less than expected.

FAQ

What is TDEE?

Total Daily Energy Expenditure — the total calories you burn in a day across basal metabolic rate (BMR), physical activity, and the thermic effect of food. TDEE is your maintenance calorie level — eating at TDEE maintains weight.

Which formula is most accurate?

Mifflin-St Jeor is the most accurate for general populations (within 10% for most individuals). No formula accounts for individual metabolic variation — treat the result as a starting estimate and adjust based on 2-4 weeks of actual results.

How much of a deficit is safe?

500 kcal/day deficit produces about 1 lb/week of weight loss — considered safe by most health authorities. Deficits above 1,000 kcal/day risk muscle loss, nutrient deficiencies, and metabolic adaptation. Consult a doctor before aggressive restriction.