How to Calculate Your TDEE (and Use It to Lose or Gain Weight)

TDEE, Total Daily Energy Expenditure, is the real number of calories your body burns in a day, resting metabolism plus everything you do on top of it. It’s the actual starting point for a genuine weight target, not the generic 2,000/2,500kcal figure most people have seen. Here’s the real, standard two-step calculation, worked through with real numbers, then how to turn it into an actual daily target.

Step 1: your BMR (the Mifflin-St Jeor equation)

BMR, Basal Metabolic Rate, is what your body burns doing nothing at all, just staying alive. The most widely used formula is the Mifflin-St Jeor equation, weight in kilograms, height in centimetres, age in years.

• Men: (10 × weight) + (6.25 × height) − (5 × age) + 5
• Women: (10 × weight) + (6.25 × height) − (5 × age) − 161

Step 2: multiply by how active you actually are

BMR alone assumes you never move. TDEE multiplies it by a real activity factor to account for everything else in your day.

• Sedentary (little to no exercise, desk job): × 1.2
• Lightly active (light exercise 1–3 days a week): × 1.375
• Moderately active (moderate exercise 3–5 days a week): × 1.55
• Very active (hard exercise 6–7 days a week): × 1.725
• Extra active (very hard exercise or a physical job): × 1.9

A real worked example

A 30-year-old woman, 65kg, 165cm tall, moderately active. BMR: (10 × 65) + (6.25 × 165) − (5 × 30) − 161 = 650 + 1031.25 − 150 − 161 = 1,370kcal. TDEE: 1,370 × 1.55 (moderately active) = 2,124kcal a day, her real, personal maintenance calories, not a generic average.

Turning TDEE into a real weight-loss or weight-gain target

To lose weight, eat below your TDEE. The NHS’s own guidance is to “aim to reduce your intake by around 600 calories a day,” which it calls “a safe and sustainable way to lose weight.” For our 2,124kcal example, that’s a target of roughly 1,524kcal a day. The NHS separately puts a safe pace of weight loss at “1 to 2lbs, or 0.5 to 1kg, a week.” To gain weight, the logic mirrors it, eat consistently above your TDEE, most commonly by 250–500kcal a day, and re-check your TDEE every few weeks since it genuinely shifts as your weight changes.

Where you will see it used on this site

You don’t need to do this maths by hand every time, our own BMR Calculator and TDEE Calculator run the exact same Mifflin-St Jeor calculation on your own real numbers. And if a calculator shows you a number that seems low, it may be showing you your BMR, not your TDEE, two genuinely different figures, covered in BMR vs. TDEE, Which Number Actually Matters.

Want your TDEE on its own, full page, with no other tabs to click through? Try our dedicated TDEE Calculator.

New to the concept entirely? What Is TDEE? A Complete, Plain-English Guide starts from the very beginning.

*This article is general information, not medical or dietary advice. If you’re making dietary changes for a specific health reason, speak to a doctor or registered dietitian.