Maintenance Calorie Calculator

TDEE and maintenance calories: the same number, two names

TDEE stands for total daily energy expenditure. It is the total energy your body uses in a day, and it is the same quantity this page calls maintenance calories. The two terms are interchangeable. It is an estimate rather than a measurement, because the equations describe an average pattern and not your exact day.

The calculator works it out by multiplying your basal metabolic rate by an activity factor. Both parts are set out in full further down this page, along with the three equations this tool runs.

There is no single TDEE formula. The figure depends on which BMR equation is used and which activity factor is applied to it, and both choices move the answer. That is why this page shows a range across three equations instead of one number.

BMR and TDEE are not interchangeable. BMR is the energy your body uses at rest. TDEE is that resting figure plus everything you do on top of it.

How many calories do I burn a day?

This is the same question as “what are my maintenance calories”, asked a different way. The calculator above answers it.

The amount you burn at rest is your BMR. The rest comes from movement, work and training.

Average figures are easy to find and not much use. A population average blends people of different sizes, ages and weekly routines, so any one person can sit well above or below it. Taking planned exercise out of the average does not fix this, because everyday movement varies between people just as much as training does.

How maintenance calories are worked out

Every estimate starts with basal metabolic rate (BMR), the energy your body spends at complete rest keeping your heart, brain, liver and kidneys running. BMR is then multiplied by an activity factor to account for everything else you do: walking, working, fidgeting and training.

The three equations here take different routes to BMR. Mifflin-St Jeor and the revised Harris-Benedict equation both work from sex, age, height and weight. Katch-McArdle ignores those and works from lean body mass instead, which is why it only appears when you supply a body fat percentage.

The equations, as this calculator runs them:

• Mifflin-St Jeor: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years), then + 5 for men or − 161 for women.
• Revised Harris-Benedict (Roza and Shizgal, 1984): for men, BMR = 88.362 + 13.397 × weight (kg) + 4.799 × height (cm) − 5.677 × age (years); for women, BMR = 447.593 + 9.247 × weight (kg) + 3.098 × height (cm) − 4.33 × age (years).
• Katch-McArdle: BMR = 370 + 21.6 × lean body mass (kg), where lean body mass is weight × (1 − body fat % ÷ 100).

Each BMR is then multiplied by your activity factor, from ×1.2 (sedentary) to ×1.9 (extra active), to give maintenance calories.

Why calculators disagree with each other

If you have tried three maintenance calorie calculators and got three different answers, nothing is broken. Two things drive the spread:

The equation. For a 30-year-old, 5′10″, 175 lb man, Mifflin-St Jeor gives about 1,760 calories a day and revised Harris-Benedict about 1,835: a gap of roughly 75 calories before any activity adjustment, and it widens once a multiplier is applied.

The activity level. This is the bigger factor by far. Moving one step up the scale, from lightly active to moderately active, raises the multiplier from 1.375 to 1.55. That is a proportion of your BMR, not a fixed number, so it grows with body size: for the 30-year-old, 5′10″, 175 lb man above it is roughly 310 calories a day. Most people overestimate here. If your job is desk-based and you train three times a week, that is “lightly active” territory, not “very active”.

Picking your activity level honestly

A note on where these multipliers come from: the 1.2 to 1.9 scale is the conventional activity-factor scale associated with the Harris-Benedict tradition. Unlike the three BMR equations cited at the bottom of this page, these factors are a widely used convention, not the product of a single validation study. That is part of why different calculators disagree. Each factor is meant to cover exercise and everyday movement together.

The descriptions on each option above are deliberately concrete. Read them as a description of your whole week, not of your best week. A useful check: if you cannot name the specific sessions or physical work that justify a level, pick the one below it. Starting low and adjusting upward from real weight data beats starting high and wondering why the scale is moving.

What this estimate can and cannot tell you

These equations were built to predict averages across groups of people. They describe a typical body with your sex, age, height and weight, not your body specifically, which can sit meaningfully above or below the prediction. That is the real limit of any calculator on this subject, including this one.

One thing the arithmetic does say plainly: every equation here takes weight as an input, so the estimate changes when your weight changes. A number calculated at one weight does not describe you at another. An old figure describes an older body, so recalculate when the scale moves.

For advice on how to act on any of this, whether that is what to eat, how to change intake, or how to read changes on the scale, talk to a clinician or a registered dietitian. This page deliberately stops at the estimate.

Who this calculator is for

These equations were developed and validated in healthy adults. The Mifflin-St Jeor study covered 498 people aged 19 to 78. This tool accepts ages 18 to 80 and is intended for healthy, non-pregnant, non-breastfeeding adults.

It is not appropriate during pregnancy or breastfeeding, for children or teenagers, for athletes with unusual training loads, or for anyone with a condition affecting metabolism, and it is not a tool for managing an eating disorder. If any of those apply, the right number comes from a clinician or registered dietitian, not from a web page.