Overview
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest just to keep you alive -- breathing, circulating blood, and maintaining organs. TDEE (Total Daily Energy Expenditure) builds on BMR by adding the calories you burn through daily activity, exercise, and digestion.
Use the BMR Calculator to find your baseline metabolism. Use the TDEE Calculator to find your actual daily calorie needs based on your activity level.
Key Differences
**What it measures:** BMR measures calories burned at absolute rest. TDEE measures total calories burned in a full day including all activity.
**Inputs:** BMR uses age, sex, height, and weight. TDEE uses BMR plus an activity multiplier based on exercise frequency and intensity.
**Practical use:** BMR tells you the minimum calories your body needs. TDEE is the number you actually use for meal planning, weight loss, or weight gain.
**Relationship:** TDEE = BMR x Activity Factor. For a sedentary person, TDEE is about 1.2x BMR. For very active people, it can be 1.9x BMR or higher.
**Common formulas:** Both commonly use the Mifflin-St Jeor equation, considered the most accurate for most adults.
When to Use the BMR Calculator
- You want to know your body's minimum calorie requirement for basic survival - You are curious about how your metabolism compares to averages for your age and sex - You want a starting point before factoring in activity for meal planning - You are interested in how weight, age, or body composition affects your baseline metabolism - You want to understand why you should never eat below your BMR
When to Use the TDEE Calculator
- You want to know how many calories to eat per day to maintain your current weight - You are planning a calorie deficit for weight loss (eat below TDEE but above BMR) - You are bulking and need to eat above TDEE to gain muscle - You want to see how changing your activity level affects your calorie needs - You are designing a meal plan and need accurate daily calorie targets
Frequently Asked Questions
Q: Should I eat at my BMR or TDEE for weight loss? A: Eat below your TDEE but above your BMR. A deficit of 500 calories below TDEE produces approximately 1 pound of weight loss per week.
Q: Why is my TDEE so much higher than my BMR? A: Even light daily activity adds 20-40% to your BMR. Exercise, walking, and even digesting food all burn additional calories.
Q: Does BMR decrease with age? A: Yes. BMR typically decreases about 1-2% per decade after age 20, mainly due to loss of muscle mass.
Q: How accurate are online BMR and TDEE calculators? A: They estimate within 5-10% for most people. For precise measurement, indirect calorimetry (a breathing test) measures BMR directly.
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