TDEE Calculator

What this is

Your TDEE is the total number of calories you burn across a full day — everything from keeping your heart beating to walking, training, and digesting food. It starts with your BMR (Basal Metabolic Rate, the energy you’d burn lying in bed all day), calculated here with the Mifflin-St Jeor equation, the most accurate of the common formulas. We then multiply BMR by an activity factor to get your real-world daily burn.

How to use it

1. Enter your sex, age, height, and weight.
2. Choose the activity level that honestly reflects a typical week — most people overestimate here.
3. Press Calculate. Your TDEE is roughly the calories to maintain your current weight.
4. To lose fat, most women eat a little below their TDEE — but not always. Depending on your history, hormones, training, and how much you have dieted before, some lose fat best in a modest deficit while others do better eating at or near maintenance and building muscle first. Use the Macros & Deficit calculator to turn this number into a starting target and protein/fat/carb split — then adjust to your body.

Limitations & the honest fine print

• It’s an estimate, not a measurement. Formulas predict the average person of your stats; your true burn can vary by 10–15%. Treat it as a starting point, then adjust based on real-world results over 2–3 weeks.
• Activity level is the biggest source of error. When in doubt, pick the lower option and let the data correct you.
• It doesn’t know your body composition. More muscle means a higher true burn than the formula predicts — another reason muscle is medicine.
• GLP-1 medications, thyroid conditions, and a history of dieting can shift metabolism meaningfully. If that’s you, individualized testing beats any formula.
• Educational only — not a substitute for personalized medical or nutrition guidance.