TDEE Calculator

How to Use the TDEE Calculator

Total daily energy expenditure is what you actually burn in a day, all in: basal metabolism, the energy cost of digesting food, incidental movement and deliberate exercise. It is the number every calorie target starts from, and the number people most often overestimate.

1. Enter your height, weight and age. These feed the Mifflin-St Jeor equation, which produces the basal rate the activity factor multiplies.
2. Choose an activity level honestly. The single most common error on this page is picking one level too high — a gym session three times a week alongside a desk job is lightly to moderately active, not very active.
3. Read the activity tile. It shows how many calories the multiplier is adding, which makes an implausible choice obvious: 600 kcal a day is a serious amount of movement.
4. Compare against the sedentary figure. The gap between sedentary and your chosen level is what your activity is worth, and seeing it in calories rather than as a multiplier makes it easier to judge.
5. Treat the result as a hypothesis. Weigh yourself over two or three weeks at a steady intake; if weight holds, that intake is your real TDEE, whatever the calculator said.

Activity factors are broad brackets that were never meant to be precise. The difference between two adjacent levels here is around 300 kcal a day, which is larger than most people's deliberate exercise.

TDEE Formula

One multiplication, applied to a basal rate.

Two components hide inside the multiplier and deserve naming. The thermic effect of food is the energy spent digesting, which runs at roughly 10% of what you eat. Non-exercise activity thermogenesis is fidgeting, standing, walking to the kitchen — and it varies between individuals by several hundred calories a day, which is a large part of why the same diet produces different results in different people.

Example

A BMR of 1,767.50 at a moderate activity level

1. Basal rate from Mifflin-St Jeor: 1,767.50 kcal.
2. Moderately active multiplier: × 1.55.
3. Total daily energy expenditure: 1,767.50 × 1.55 = 2,739.63 kcal.
4. Energy from activity: 2,739.63 − 1,767.50 = 972.13 kcal.
5. Basal metabolism is 1,767.50 ÷ 2,739.63 = 64.52% of the daily total.
6. Per kilogram of body weight, the total is 33.41 kcal.

What one level costs

The same body at sedentary would burn 1,767.50 × 1.2 = 2,121 kcal. The gap between sedentary and moderately active is 618.63 kcal a day — roughly 4,300 calories a week, or well over half a kilogram of body tissue a month if intake does not change. That is the entire reason activity level matters more than which BMR formula you pick.

Why overestimating is so easy

The step from moderately active to very active adds 309 kcal a day. Very active means hard exercise six or seven days a week — not four gym sessions and a busy job. Choosing it wrongly builds a 300-calorie error into every target derived from the figure, which is enough to turn an intended deficit into maintenance.

Correcting the Estimate With Real Data

Your basal rate at every activity multiplier.

Each step is worth roughly 310 kcal. Across the whole range the difference is 1,237 kcal a day — more than a third of the largest figure — which tells you that activity level, not body size, is the variable doing most of the work here.

The honest way to use this page is as a first guess to be corrected. Set an intake at the calculated maintenance level, hold it steady for three weeks, and weigh yourself under the same conditions each time. If weight is stable, the estimate was right. If it drifts, the real figure is roughly 7,700 kcal per kilogram of change spread over the period — which lets you correct the number directly rather than arguing about multipliers.

That feedback loop beats any equation, because it measures you rather than a population average. It also catches the two largest sources of error at once: a misjudged activity level and an underestimate of what you actually eat, which research consistently finds runs 20% or more below reality.

Four Reasons Your Real TDEE Differs

Four reasons your real TDEE differs from the number above.

Incidental movement varies enormously. Two people with identical jobs and gym schedules can differ by several hundred calories a day in fidgeting, posture and unplanned walking. No activity bracket captures that, and it is one of the better-documented reasons identical diets produce different outcomes.

Expenditure falls as you lose weight. A smaller body costs less to run, so a deficit that worked at the start of a diet becomes maintenance later. Recalculate every four or five kilograms rather than holding the original target.

Exercise calories are usually overstated. Fitness trackers and gym machines routinely report 20% to 50% more than laboratory measurement, and eating those calories back is a reliable way to stall. Treat the activity factor as already including your exercise rather than adding it twice.

Adaptation is real but smaller than folklore suggests. Sustained dieting reduces expenditure by more than body size alone predicts, typically in the 5% to 15% range. That is a genuine headwind and not the metabolic shutdown sometimes described.

The multipliers are coarse by design. Five brackets have to cover everything from a desk job with no exercise to a labourer who also trains, and the steps between them are large. At this body size one bracket is worth roughly 310 calories a day, so choosing between moderately and very active moves the answer by more than a substantial meal.

Most people over-select. The bracket names invite you to describe the week you intend to have rather than the one you actually had, and three gym sessions across seven mostly sedentary days is closer to lightly active than to moderate. If in doubt, pick the lower bracket and let the scale correct upwards — that error is cheaper to fix than the other one.

The alternative to guessing is to stop guessing. Track intake honestly for two weeks alongside weekly average weight, and the arithmetic gives you a measured maintenance figure specific to you. Any multiplier is a stand-in for that measurement, useful only until you have made it.

Once you have a figure you trust, the calorie calculator turns it into cutting and bulking targets with the weekly weight change each implies, and the macro calculator splits the result into grams.