Calorie Calculator, Daily Intake by Age, Activity & Goals

What is TDEE?

Total Daily Energy Expenditure (TDEE) is the total number of calories you burn in a day, including your basal metabolism, physical activity, and the energy used to digest food. Understanding your TDEE is the foundation for any nutrition plan.

Calorie Deficit and Surplus

• Weight loss: Eat fewer calories than your TDEE. A 500-calorie daily deficit leads to roughly 1 pound of fat loss per week.
• Weight gain: Eat more calories than your TDEE. A 500-calorie daily surplus supports about 1 pound of weight gain per week.
• Maintenance: Eat approximately your TDEE to maintain your current weight.

Why 500 Calories ≈ 1 lb/Week

One pound of body fat stores approximately 3,500 calories. A deficit of 500 calories per day over 7 days totals 3,500 calories, resulting in roughly one pound of fat loss. This is an approximation, as metabolism adapts over time.

Macronutrient Balance

A common balanced split for general health is:

• Protein: 30% of calories (supports muscle maintenance)
• Carbohydrates: 40% of calories (primary energy source)
• Fat: 30% of calories (hormones and nutrient absorption)

When to Use This Calculator

• Starting a diet: Find your maintenance calories before creating a deficit to avoid under-eating.
• Weight loss plateau: Re-calculate after losing 10+ lbs, since your TDEE changes as your weight changes.
• Muscle building: Determine the right surplus before a bulking phase, 200-300 calories over TDEE minimizes fat gain.

Real-World Examples

Example 1, Weight loss: 35-year-old male, 5'9", 195 lbs, moderately active. TDEE ≈ 2,700 cal. Loss target: 2,200 cal/day. Expected rate: 1 lb/week. Adjust after 4-6 weeks based on actual results.

Example 2, Maintenance after goal: 28-year-old female, 5'5", 135 lbs, lightly active. TDEE ≈ 1,820 cal. She can eat 1,750-1,900 cal/day and expect stable weight.

Limitations & Assumptions

• Accuracy is typically ±10% - individual metabolism varies due to genetics, hormones, and gut microbiome.
• The Mifflin-St Jeor formula is validated for adults 18-65 with average body composition.
• Activity multipliers are approximations, fitness trackers often overestimate calorie burn by 15-30%.
• Does not account for adaptive thermogenesis, metabolism slows during prolonged caloric restriction.

Data Sources

BMR formula: Mifflin-St Jeor equation (1990), validated in Frankenfield et al. (2005) as the most accurate for non-obese individuals. Activity multipliers from the Harris-Benedict revision (Roza & Shizgal, 1984). Deficit/surplus relationship per National Institutes of Health (NIH) guidelines.

Related Data

Track calories and nutrition facts for 2M+ foods at USDA FoodData Central. Explore vitamin and supplement data at NIH ODS.

Disclaimer: This calculator provides estimates for informational purposes only. Consult your healthcare provider for medical advice.