BMR vs TDEE: Which Calorie Number Should You Use?

Use TDEE (total daily energy expenditure) for planning what to eat, not BMR. Your basal metabolic rate (BMR) is the energy your body burns at complete rest, just to keep you alive. TDEE adds everything else you do in a day, so it is the number that actually corresponds to "calories to maintain my weight". BMR is the foundation the TDEE estimate is built on.

Both figures are estimates from an equation, not measurements, and individual needs vary. Treat them as a starting point rather than medical or nutritional advice.

What is BMR, exactly?

BMR covers breathing, circulation, keeping your body warm, and cell repair: the cost of being alive while lying still. For most people it is the largest part of daily energy use, often well over half.

Measuring BMR properly takes lab equipment. Calculators estimate it from sex, age, weight and height. The equation used here is Mifflin-St Jeor, one of the most widely used formulas today:

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

A worked example

A 30-year-old woman who weighs 65 kg and is 168 cm tall:

• 10 × 65 = 650
• 6.25 × 168 = 1,050
• 5 × 30 = 150
• 650 + 1,050 − 150 − 161 = 1,389 kcal/day

That is her estimated BMR.

How do you get from BMR to TDEE?

Multiply BMR by an activity factor:

Activity level	Factor
Sedentary (little or no exercise)	1.2
Light (1–3 days/week)	1.375
Moderate (3–5 days/week)	1.55
Active (6–7 days/week)	1.725
Very active (physical job + training)	1.9

If the woman above exercises lightly, her TDEE is 1,389 × 1.375 ≈ 1,910 kcal/day. That is her estimated maintenance intake.

The activity factor makes a large difference. A 45-year-old man at 85 kg and 180 cm has a BMR of 1,755 kcal. Sedentary, his TDEE is about 2,106 kcal. With moderate exercise it is about 2,720 kcal, more than 600 calories higher.

Which number should you use for what?

• Planning daily meals: TDEE. It is your estimated maintenance level.
• Setting a calorie deficit: subtract from TDEE, not from BMR.
• Comparing over time: BMR. It changes with weight and age only, so it shows how your baseline shifts, separate from how active you were that month.
• Choosing a floor: many people use BMR as a rough lower limit, since eating far below it for long periods is hard to sustain.

What about weight-loss targets?

The calculator shows two targets below TDEE:

• Mild weight loss (≈ −0.25 kg/week): TDEE − 275 kcal. For the example woman, about 1,635 kcal/day.
• Weight loss (≈ −0.5 kg/week): TDEE − 550 kcal. About 1,360 kcal/day.

These rest on the common rule of thumb that a kilogram of body fat stores roughly 7,700 kcal: 550 kcal a day for seven days is 3,850 kcal, about half a kilogram. Real-world results vary because the body adapts and water weight fluctuates.

Why do the estimates change with age?

The equation subtracts 5 kcal for every year of age. Keep everything else the same and a 25-year-old man at 85 kg and 180 cm has a BMR of 1,855 kcal, 100 kcal more than at 45. Part of the real-world decline comes from losing muscle, which is why strength training is often recommended as people get older.

How to use the BMR Calculator

The BMR Calculator needs five inputs:

1. Choose your Sex (the equation has a different constant for each).
2. Enter Age in years, Weight in kilograms and Height in centimeters. If you think in pounds or feet, convert first with the Weight Converter.
3. Pick your Activity level. Be honest; most people overestimate this one.
4. Read your Basal metabolic rate (BMR), the Daily calories to maintain weight (TDEE), and the two weight-loss targets.

Everything is calculated in your browser as you type. Food labels in some countries list kilojoules instead of calories; one kilocalorie is 4.184 kJ, so 1,910 kcal is about 7,991 kJ.

Common mistakes to avoid

• Counting exercise twice. If you pick "Active" and then also add calories back from a fitness tracker, you double count.
• Using an old weight. Recalculate after every few kilos of change.
• Treating the result as exact. Equations like this can be off by around 10% for an individual. Adjust based on what your weight actually does over a few weeks.

FAQ

Is Mifflin-St Jeor better than the Harris-Benedict equation?

Mifflin-St Jeor was published later and is generally considered closer to measured values for modern populations, which is why many dietitians use it. Neither accounts for body composition directly.

Why is the BMR lower than the calories I seem to burn?

Because BMR excludes all movement and digestion. Your actual daily burn is the TDEE figure, and even that is an estimate.

Can I use this if I am very muscular?

You can, but the equation uses total weight, not lean mass, so it may underestimate the needs of very muscular people.

Get your BMR and TDEE estimates in seconds with the BMR Calculator.