TDEE calculator: free Mifflin-St Jeor estimate

TDEE stands for Total Daily Energy Expenditure, the total number of calories your body burns across a full day. It is the single most useful number in nutrition, because it is the line that separates losing weight from gaining it. Eat below your TDEE and you tend to lose, eat above it and you tend to gain, eat right at it and your weight holds steady. That is why TDEE is also called your maintenance calories.

TDEE is built from two pieces. The first is your Basal Metabolic Rate (BMR), the calories your body spends at complete rest just keeping you alive: breathing, pumping blood, repairing cells, and running your organs. For most people BMR is the largest single chunk of the day, often 60 to 70 percent of the total. The second piece is everything you burn on top of rest: walking, training, fidgeting, standing, and even the energy it takes to digest your food.

To turn BMR into TDEE, you multiply it by an activity factor that reflects how much you move. A desk worker who rarely exercises sits near the bottom of the range, while someone training hard most days or working a physical job sits near the top. The calculator below handles both steps for you: it estimates your BMR, applies the activity factor you choose, and shows your maintenance calories instantly.

This page is built for the calculator itself. For the full picture of what TDEE actually is, what it is built from, and why yours keeps changing, see what is TDEE, and why does yours keep changing. And since the number below is a single point estimate, not a fixed target, maintenance calories are a range, not a magic number covers why.

The calculator uses the Mifflin-St Jeor equation, the formula most dietitians and researchers reach for because it tracks measured energy expenditure more closely than older equations for the general population. It estimates your BMR from four inputs: weight, height, age, and sex. The formula works in metric units, so pounds are converted to kilograms and feet and inches to centimeters first.

The two BMR formulas are:

• Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
• Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

Once you have BMR, you multiply it by an activity factor to get TDEE. These multipliers are the standard buckets used across the field:

• Sedentary (1.2): little or no exercise, mostly seated days
• Lightly active (1.375): light exercise 1 to 3 days a week
• Moderately active (1.55): moderate exercise 3 to 5 days a week
• Very active (1.725): hard exercise 6 to 7 days a week
• Extra active (1.9): hard daily training or a physically demanding job

So a 30-year-old man weighing 80 kg at 178 cm has a BMR of about 1,766 calories. At a moderate activity factor of 1.55, his estimated TDEE is roughly 2,737 calories a day. The activity multiplier is the roughest part of the calculation, since real-world movement does not fall neatly into five buckets, which is exactly why the number is a starting estimate rather than a verdict.

Your TDEE is a maintenance line, not a target to obsess over. If your goal is fat loss, eating somewhat below it nudges your body to draw on stored energy. If your goal is building muscle, eating somewhat above it gives you the surplus to grow. A moderate, sustainable gap is almost always easier to hold than a drastic one, and pairing any change with enough protein and some strength work helps you keep muscle through the process.

The most reliable way to use the number is to treat it as a hypothesis. Pick a daily intake, hold it steady for two to three weeks, and watch where your weight trend actually goes. If it moves the way you want, your number is right. If it stalls or moves the wrong way, adjust by a couple hundred calories and watch again. Your body, not a calculator, has the final say, and letting the trend correct the estimate beats recalculating a formula over and over.