TDEE Calculator

What It Does

Estimate the energy your body spends in a day. The page multiplies your basal metabolic rate — what a resting body needs — by one of five activity factors, from 1.2 to 1.9, to reach total daily energy expenditure: the calories that hold your weight steady. Alongside it you get the same figure for every other activity level, and a goal band of ±250 and ±500 kcal a day in both kilocalories and kilojoules. These are population estimates, not a measurement of your metabolism.

Real-World Usage

Athletes use the figure to set a calorie target for a training block and to judge whether a plateau is a measurement error or a real change. Dietitians start a weight-loss plan from the maintenance number and step the deficit down from it rather than jumping straight to the deepest one. Fitness trackers estimate the same quantity from heart rate and step data, and the two figures rarely agree exactly — what this page adds is arithmetic you can see and repeat. Macronutrient plans are built on a calorie total too, so the TDEE number comes first and the protein, fat and carbohydrate split follows.

Local Context

Kilocalories are the unit used in the United States and in most fitness writing, while European, Australian and New Zealand food labels print kilojoules: one kilocalorie is 4.184 kilojoules, and both columns are shown here so a label in either unit can be compared with the target. The activity factors themselves are the same everywhere — they come from the published physical activity level scale, which starts at 1.2 for a sedentary week and stops at 1.9.

Choosing an Activity Level

Most disagreement about a TDEE figure comes from the activity level, not the formula. Count the days you actually train in a normal month and include work: a nurse, a teacher on their feet and a warehouse picker are not sedentary even if they never enter a gym. If two levels seem to fit, take the lower one — the estimate will then be wrong in the safer direction, and two weeks of body-weight data will tell you more than any formula.

How Accurate Is This?

Mifflin-St Jeor predicts resting energy expenditure for a group within roughly 10 percent, which is a useful planning figure and a poor individual measurement. It does not know your muscle mass, your thyroid, your medication or how much you fidget. Treat the maintenance number as a starting point, eat at it for two to three weeks and compare your weight: if it has not moved, the estimate was right; if it has, adjust the target by the difference rather than recomputing the formula.

Calorie Needs by Age and Sex

Published reference intakes place an adult's daily requirement in the ranges below. They come from the estimated energy requirement equations reprinted in the Dietary Guidelines for Americans (Appendix 2), calculated for a reference man of 178 cm and 70 kg and a reference woman of 163 cm and 57 kg. The low end of each range is a sedentary week and the high end an active one. Read them as a sanity check on the number above, not as a target: body size and activity move the figure, and that is what this page asks you for.

How many calories do I need to maintain my weight?

Your maintenance level is the TDEE this page reports for the activity level you selected. Eating close to that figure on most days holds your weight steady; the goal band shows what a daily deficit or surplus of 250 and 500 kcal would look like.

Which activity level should I choose?

Pick the level that matches an ordinary week, not your best one. Sedentary means little or no exercise, light means one to three sessions, moderate three to five, very active six to seven, and extra active means hard training twice a day or a physical job.

Is a 500 calorie deficit safe?

For most adults 500 kcal a day is a moderate pace: roughly 0.45 kg a week at 7,700 kcal per kilogram of body fat. A target under the low-intake floor named on the page is below what an ordinary mixed diet can cover without supervision.

Why does the calculator show kcal and kJ?

European, Australian and New Zealand food labels print energy in kilojoules, while the United States and most fitness writing use kilocalories. One kilocalorie is 4.184 kilojoules, so both columns describe the same target in the unit you have to hand.

Does the estimate account for muscle mass?

No. Mifflin-St Jeor uses weight, height, age and sex, so two people of the same build with different amounts of muscle can share a figure. If you know your body-fat percentage, it is the better input for setting an energy target.