How to calculate TDEE and calories

Basal calories on these pages are the Mifflin-St Jeor estimate of energy used at rest. Total daily energy expenditure, the TDEE line, is that figure times an activity factor you pick. The calorie calculator and the TDEE calculator share the equation. The calorie page then lists six fixed offsets from the day total. The TDEE page can also split the day total into grams of protein, carbohydrate, and fat.

Both results are planning estimates. They are not medical advice, not a diet prescription, and not a measurement of what you ate. The equation was studied in adults. An age under 18 still calculates, and the page warns. Talk with a clinician or a dietitian before you change how you eat or train.

Mifflin-St Jeor here is (10 × kilograms) + (6.25 × centimeters) − (5 × age in years) + 5 for male or − 161 for female. Sedentary multiplies by 1.2, light by 1.375, moderate by 1.55, active by 1.725, and very active by 1.9. The labels describe a desk day, easy exercise on 1–3 days, training on 3–5 days, hard training on 6–7 days, and a physical job plus hard training. The factor is your choice. The page does not infer it from a step count.

Each of the two results is rounded to the nearest calorie after its own step. The activity factor multiplies the unrounded basal figure, not the already rounded one. That is why a displayed basal calorie and 1.2 times that displayed calorie can disagree by one calorie. Read the steps when you want the raw product.

A 30-year-old man at 80 kg and 180 cm is (10 × 80) + (6.25 × 180) − (5 × 30) + 5. That is 800 + 1,125 − 150 + 5 = 1,780. The basal line is 1,780 kcal because the raw figure is already a whole number. Moderate multiplies 1,780 by 1.55, which is 2,759, also already whole. Rounding does not move either line.

On the TDEE page a balanced 30/40/30 split of that 2,759 kcal day uses 4 kcal per gram of protein, 4 kcal per gram of carbohydrate, and 9 kcal per gram of fat. Protein is 0.30 × 2,759 / 4 = 206.925, shown as 206.9 g. Carbohydrate is 0.40 × 2,759 / 4 = 275.9 g. Fat is 0.30 × 2,759 / 9 = 91.966, shown as 92 g. Higher protein, 40/30/30, swaps the protein and carbohydrate grams and leaves fat at 92 g.

The calorie calculator opens on a 30-year-old woman at 65 kg and 165 cm, light activity. The raw basal figure is (10 × 65) + (6.25 × 165) − (5 × 30) − 161 = 650 + 1,031.25 − 150 − 161 = 1,370.25, shown as 1,370 kcal. Light multiplies 1,370.25 by 1.375. That product is 1,884.09375, which rounds to 1,884 kcal. Multiplying the already rounded 1,370 by 1.375 would be 1,883.75 and would round to 1,884 as well in this particular case. The page still uses the unrounded path.

From 1,884 the six targets subtract 750, 500, or 250, or add 0, 250, or 500. They are 1,134, 1,384, 1,634, 1,884, 2,134, and 2,384. The labels call the losses about 1.5 lb, 1 lb, and 0.5 lb a week, then maintenance, then the two gain steps. Those pounds are a caption on a fixed calorie offset, not a second equation. A target that is above zero and under 1,200 is marked to use caution. 1,134 is that row. The page floors a target at zero, so a small day total cannot print a negative calorie goal.

Pounds become kilograms by multiplying by 0.45359237. Feet and inches become centimeters by way of total inches times 2.54. A 45-year-old woman at 150 lb and 5 feet 6 inches is 68.04 kg and 167.64 cm. The raw basal figure is 1,342.14, shown as 1,342 kcal. Sedentary multiplies the unrounded 1,342.14 by 1.2, and 1,610.57 rounds to 1,611 kcal. Rounding 1,342 first and then multiplying by 1.2 would land on 1,610. The steps keep the raw basal value so you can see which route the page took.

A height of zero is refused. Age has to be greater than zero and at most 120. Height outside 120 to 230 cm, or weight outside 30 to 300 kg, still calculates and adds a warning that the measurement is outside the usual adult range. Check the unit before you trust a warning. A kilogram typed into a pounds field is a different person.

The equation does not know muscle, a medical condition, a pregnancy, or whether the activity row matches the week you actually lived. Custom macro percents on the TDEE page have to add to 100. A 30/40/20 split is refused. The calorie page does not split grams at all. If you want grams, use the TDEE calculator after you have the day total.

Nothing is stored after you leave the tab. The numbers are not a food log. Use them to set a starting point you can compare with what you actually eat, and change course with a qualified professional if the plan is for health rather than for checking the arithmetic.

A 25-year-old woman at 70 kg and 170 cm on the moderate row is (10 × 70) + (6.25 × 170) − (5 × 25) − 161. That is 700 + 1,062.5 − 125 − 161 = 1,476.5. The basal line rounds to 1,477 kcal. Moderate multiplies the unrounded 1,476.5 by 1.55, which is 2,288.575, and that rounds to 2,289 kcal. Multiplying the displayed 1,477 by 1.55 gives 2,289.35, which also rounds to 2,289. The steps still show 1,476.5 so you can see the raw product when the two routes differ on another input.

The six calorie-page targets from 2,289 are 1,539, 1,789, 2,039, 2,289, 2,539, and 2,789. None is under 1,200, so the caution mark stays off. The same woman on the sedentary row uses 1.2 instead of 1.55. 1,476.5 × 1.2 = 1,771.8, which rounds to 1,772 kcal. Changing only the activity row shows the factor without rebuilding the basal equation.

The TDEE page’s lower-carb preset is 35 percent protein, 25 percent carbohydrate, and 40 percent fat. On 2,759 kcal, protein is 0.35 × 2,759 / 4 = 241.4125, shown as 241.4 g. Carbohydrate is 0.25 × 2,759 / 4 = 172.4375, shown as 172.4 g. Fat is 0.40 × 2,759 / 9 = 122.622, shown as 122.6 g. The gram line uses one decimal. Those percents add to 100. A custom split that adds to 90 is refused.

The calorie calculator does not split grams. Use it for the day total and the six offsets. Use the TDEE calculator when you want grams from the same equation. The grams follow the rounded TDEE. In this example 2,759 is already whole, so the rounding choice does not move the grams.

Pounds typed into the kilogram field, or centimeters typed into the inch field, are the usual miss. Imperial mode multiplies pounds by 0.45359237 and total inches by 2.54 before the equation. Five feet six inches is 66 inches, and 66 × 2.54 is 167.64 cm, not 66. If a warning says the height is outside 120 to 230 cm, check the unit before you touch the activity row.

Age is in years. A 16-year-old still gets a number plus the adult-study warning. Age 121 is refused. A blank weight is refused. The result remains a planning estimate, not medical advice, and it does not change because one week was harder than the row you selected.