In this article (7 sections)
TDEE means total daily energy expenditure: the energy used at rest, digesting food, moving through daily life and exercising. It is different from the active-calorie number on a watch.
For population context, read how many calories per day. The daily calorie needs guide focuses on equation inputs and several profiles. This guide focuses on using that estimate without confusing resting, active and total energy.
Step 1: estimate resting energy expenditure
The original Mifflin-St Jeor study predicts resting energy expenditure (REE). Calculators often label this BMR, although basal and resting measurements use different conditions.
- Male equation: 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5.
- Female equation: 10 x weight (kg) + 6.25 x height (cm) - 5 x age - 161.
For a 30-year-old woman weighing 70 kg (154 lb) at 168 cm (about 5 ft 6 in), predicted REE is 700 + 1,050 - 150 - 161 = 1,439 kcal/day. The sex coefficient comes from the original equation; the calculation does not directly measure body composition or individual metabolism.
Step 2: apply an activity assumption
Common calculator factors are 1.2, 1.375, 1.55, 1.725 and 1.9. They are extra assumptions, not part of the original REE equation. The calorie calculator uses this type of approach.
| Assumed factor | Same REE x factor | Rounded daily estimate |
|---|---|---|
| 1.2 | 1,439 x 1.2 | 1,727 kcal |
| 1.375 | 1,439 x 1.375 | 1,979 kcal |
| 1.55 | 1,439 x 1.55 | 2,230 kcal |
This table shows sensitivity to the choice of factor. It does not establish which factor fits this person. Consider work, transport, household movement and exercise together; training frequency alone cannot determine the answer.
Active calories versus total calories: what is the difference?
| Term | Usually describes | Check before using it |
|---|---|---|
| Resting calories | Estimated energy used at rest | Whether the device uses a full-day estimate |
| Active calories | Energy attributed to movement above a resting baseline | The device's definition and recording period |
| Workout total calories | Activity plus resting energy during that workout | Whether resting energy is included |
| Daily total calories | Resting plus activity estimates over the day | Whether the day is complete and what the model includes |
Device definitions vary. A display of 400 active calories does not mean your whole body used only 400 calories that day. It also does not automatically grant an extra 400 calories to eat.
For example, the walking guide calculates a one-hour walk at 75 kg (165 lb) and 3.8 MET as about 299 gross kcal. After subtracting a conventional 1-MET resting baseline, the same example is about 221 net kcal. These are estimates of the same walk with different accounting boundaries.
Should you eat back exercise calories?
First identify the budget method. If the activity factor already covers your usual walks and training, adding those workouts again counts them twice. If a plan starts from a baseline that excludes exercise, its adjustment method needs to be understood before adding device calories.
There is no universal rule to add all, half or none of every watch reading. Device estimates and activity multipliers are uncertain, and unusual activity may need separate consideration.
How does TDEE relate to a calorie deficit?
A deficit means intake below actual expenditure over time. If assumed maintenance is 2,200 kcal and entered intake is 1,900, the calculated difference is 300 kcal/day. That does not prove a measured deficit or predict a particular weekly loss.
The CDC describes gradual weight loss of about 1-2 lb per week as general guidance, not a rate everyone should pursue. Smaller changes may be appropriate; individual health, nutrition and starting circumstances matter. See how large a calorie deficit before choosing a restrictive target.
REE or BMR is not a universal minimum safe intake. An intake above it is not automatically adequate either. Clinical suitability depends on more than comparing two numbers. Children, pregnancy, breastfeeding, eating-disorder history and medical treatment require different assessment from this generic adult calculation.
How do you review the estimate over time?
Check equation inputs, activity assumptions and food-record completeness. If you choose to track weight, use comparable conditions and interpret the pattern rather than a single reading. Fluid changes and uncertain food entries prevent this from being an exact TDEE measurement.
NIDDK explains why weight-management energy needs change. A fixed 3,500-kcal-per-pound rule cannot reliably forecast progress indefinitely. A plateau can prompt review; it does not establish the cause or automatically justify eating less.
Frequently asked questions
Are active calories the same as TDEE?
No. Active calories usually describe movement above a resting baseline. TDEE includes resting energy and the rest of daily expenditure. Check a device's specific definitions.
How do I calculate TDEE in pounds and inches?
Convert pounds to kg by dividing by about 2.205 and inches to cm by multiplying by 2.54, then use the REE equation and an activity assumption. The daily-needs guide includes more examples.
Does a calorie deficit guarantee a pound a week?
A formula-based difference cannot guarantee a rate. Expenditure changes, intake records have uncertainty, and total weight includes more than fat. See calories in a pound of fat.