Use our free tdee calculator. Plug in your details and it gives you the calories you burn in a normal day—no effort required. This brief guide explains what that number means, where the figures come from, and how to use it without sabotaging yourself later on.
What TDEE actually measures
Your TDEE—Total Daily Energy Expenditure—is the total calories your body burns in 24 hours just to stay alive and stay active. It’s not just the food you eat; it’s the energy for breathing, digesting, walking to the kettle, and fidgeting while you wait. Every movement counts, from waking up to falling asleep.
The number comes from four main components: your Basal Metabolic Rate (BMR), the calories burned lying completely still for a day, plus the calories from daily activity—from typing to gardening—and the calories your body uses to digest food. Most calculators take your age, weight, height, and sex, feed them into a formula like Mifflin-St Jeor, then multiply the result by an activity factor you choose from a list.
Take a 32-year-old woman weighing 70 kg, 170 cm tall, who works at a desk but walks her dog for half an hour each evening. Her BMR using Mifflin-St Jeor is about 1,450 kcal. Multiply that by 1.55 for her activity level and you get a TDEE of roughly 2,250 kcal. Eat that much and she’ll stay exactly where she is now.
The definition gets shaky once you leave textbook cases. Pregnant women, breastfeeding mothers, people with thyroid issues, or anyone who’s just begun heavy training can see their TDEE rise or fall by 20% or more without warning. Even seasoned athletes sometimes forget that “moderately active” on a calculator doesn’t match the week they spent at a tournament with seven matches a day.
How the numbers get crunched
- Enter your weight, height and age.
- Pick your sex and honest activity level.
- Read your TDEE, your BMR, and calorie targets for loss or gain.
BMR (Mifflin–St Jeor) × activity factorTDEE vs Calorie Intake for Common Goals
| Goal | Daily Calorie Needs (TDEE) | Calories to Maintain Weight |
|---|---|---|
| Sedentary (little/no exercise) | 2,000 kcal | 2,000 kcal |
| Lightly Active (1-3 workouts/week) | 2,200 kcal | 2,200 kcal |
| Moderately Active (3-5 workouts/week) | 2,400 kcal | 2,400 kcal |
| Very Active (6-7 workouts/week) | 2,700 kcal | 2,700 kcal |
| Extremely Active (athlete/training 2x/day) | 3,000 kcal | 3,000 kcal |
Why this number changes everything
The danger is in guessing instead of measuring. A man who thinks he burns 3,000 kcal a day because he walks his dog but actually burns 2,400 kcal will put on half a stone in three months if he keeps eating like a labourer. Women who slash calories without checking their TDEE often end up exhausted, hungry, and stuck—despite eating less than they thought. Once you know your real number, the food diary makes sense and the changes you make actually start to work.
Three real-world walks through the maths
Desk worker with weekend walks
A 28-year-old man, 90 kg, 185 cm, desk job but runs 5 km three times a week. BMR ≈ 1,950 kcal using Mifflin-St Jeor. Multiply by 1.725 for his activity level to get 3,370 kcal. That’s the line in the sand: eat more and he’ll gain, eat less and he’ll lose.
Odd weight and mixed units
A 42-year-old woman, 68.3 kg, 162 cm, lifts weights twice a week. Her BMR is 1,430 kcal. She mistakenly uses 1.55 instead of 1.525 for her activity level. That small error turns a 2,180 kcal TDEE into 2,210 kcal—easy to miss but enough to stall progress over six weeks.
The errors that cost you weeks
| Common mistake | What to do instead |
|---|---|
| Picking the activity level that sounds best instead of the one that fits | Go by the actual hours you move, not the level that gives you the number you want. An office worker who picks ‘very active’ will overestimate by 400–600 kcal and wonder why the weight isn’t shifting. |
| Forgetting to update after a big weight change or new training block | Re-run the calculator every four to six weeks or whenever you’ve lost more than 3 kg or added a new sport. A 5 kg drop can shave 100–150 kcal off your TDEE without you noticing. |
| Mixing metric and imperial units in the same input | Stick to one system—either kg and cm or lb and inches—otherwise the BMR formula gives nonsense. A 10-stone 6-lb person who types 170 cm instead of 170 lb will get a BMR that’s off by nearly 200 kcal. |
Grab our free TDEE calculator here
| Tool | What it does |
|---|---|
| TDEE Calculator | Find your maintenance calories — the energy you burn in a typical day. |
Try the TDEE Calculator
Skip the manual maths — enter your numbers and get the answer instantly.
Open the TDEE Calculator →One last thing to double-check
Remember that these figures are general guides, not medical advice. Bodies differ, so treat the result as a starting point and speak to a qualified professional before making decisions about your health.
Quick rules to keep you on track
- Your TDEE isn’t fixed; it shifts with weight, age, and training load—recalculate every month.
- Activity factors are the biggest source of error—pick the one that matches your real week, not the one that sounds heroic.
- Use the free TDEE calculator as your starting point, then adjust up or down in 100–150 kcal steps until the scales move the way you expect.
Frequently asked questions
What is TDEE?
TDEE is total daily energy expenditure, the calories you burn in an average day including activity. It represents your maintenance level, so eating below it tends to cause weight loss and eating above it tends to cause gain.
How is TDEE calculated here?
The tool finds your BMR with the Mifflin-St Jeor equation from weight, height, age and sex, then multiplies it by an activity factor from 1.2 for sedentary up to 1.9 for extra active. The result is your estimated maintenance calories.
Which activity level should I pick?
Choose the one that honestly reflects your week, not your best days. Activity level shifts the result more than any other input, so overestimating it inflates your TDEE and can stall the progress you were aiming for.
How accurate is the number?
It is an estimate from a population formula, not a lab measurement. People with the same stats can burn different amounts, so treat it as a starting point and adjust based on how your weight actually changes over a few weeks.
Is this medical advice?
No. It is general information for planning. If you have a health condition, are pregnant, or are making significant changes to your diet, speak with a doctor or registered dietitian before acting on these figures.
