Free Online BMR and TDEE Calculator, Calories at Rest and With Activity
See how many calories your body uses. Enter your age, height, weight and sex to get your basal metabolic rate, the calories you burn at complete rest, then pick an activity level for your total daily energy expenditure. Three formulas are offered, Mifflin-St Jeor, Harris-Benedict and Katch-McArdle, so you can compare them.
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BMR & TDEE CalculatorCalories at rest, then with your activity added.
Everything is worked out in your browser. No number you type is sent anywhere, and there is no account.
About you
Nothing is uploaded; every number stays in your browser.
years
The formulas use different constants for each.
cm
ft
in
kg
lb
%
Only used by the Katch-McArdle formula.
Result
The save button in the top bar keeps the numbers you have filled in, on this device only.
Units and numbers
Display
Size
Theme
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History
Your data
Settings, history and saved setups live in this browser and nowhere else. There is no account and no server, which also means clearing them here is final.
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Your basal metabolic rate is the energy your body spends just staying alive, lying still and not
digesting: heartbeat, breathing, keeping warm. It is the biggest part of what you burn. Total daily
energy expenditure is that BMR multiplied by an activity factor, from 1.2 for a desk life up to 1.9
for hard physical work, and it is the figure you eat against to hold your weight.
Mifflin-St Jeor is the one to start with. It is the most accurate of the three for most
people. Harris-Benedict is the older standard and reads a little higher. Katch-McArdle works from
your lean mass instead of height and age, so it is the best choice if you know your body fat and
worst if you are only guessing it.
The activity multiplier is where the error lives. The BMR formulas are tight, but jumping
a level, say from lightly to moderately active, can move the calorie figure by hundreds. Pick the
level honestly, treat the result as a starting point, and correct it against what your weight
actually does over two or three weeks.
Where Your Input Goes
Nowhere. And you can check that yourself.
Your age, height and weight are worked out in your browser and never sent anywhere.
It is all done by your own browser. Press F12, open the Network tab, and use the tool:
the page fetches its own code and nothing else. Or load the page, turn off your wifi, and
carry on. It still runs, because there was never a server in the middle.
How to Calculate BMR and TDEE
A few steps, and nothing is uploaded.
1
Enter your age, sex, height and weightIn metric or imperial. Nothing is uploaded.
2
Pick an activity levelFrom sedentary to extra active; be honest, it moves the figure a lot.
3
Choose a formulaMifflin-St Jeor is recommended; Katch-McArdle needs your body fat.
4
Read BMR and TDEEYour rate at rest, and the calories to maintain your weight at every activity level.
What to Know About BMR and TDEE
Including the things this tool cannot do.
BMR is energy at rest; TDEE adds movement. Basal metabolic rate is what you burn doing nothing at all, and it is most of your daily total. Multiplying it by an activity factor gives your total daily energy expenditure, which is the number you eat against to keep your weight steady.
Mifflin-St Jeor is the most reliable of the three. Harris-Benedict is the older standard and tends to read higher. Katch-McArdle uses lean body mass, so it is the most accurate when you truly know your body fat percent and the least when you are guessing it. The tool offers all three so you can compare.
The activity multiplier carries most of the uncertainty. The formulas for BMR are tight, but the jump between activity levels can shift the calorie figure by hundreds. Choose the level honestly and adjust the result against what actually happens to your weight over a few weeks.
This is a starting estimate, not a prescription. Real metabolism varies with muscle, hormones, sleep and history in ways no formula captures. Use the number as a sensible place to begin, then let your own results, not the calculator, have the final say.
Key Features & Capabilities
What this tool does, and what it deliberately does not.
BMR and TDEEYour rate at rest and your maintenance calories.
Every activity levelThe maintenance figure at all five activity levels at once.
Three formulasMifflin-St Jeor, Harris-Benedict and Katch-McArdle.
Metric or imperialCentimetres and kilograms, or feet and pounds.
History and savedRecent results and named setups, on this device only.
Nothing uploadedYour details stay in the browser.
About the BMR & TDEE Calculator
Before you can plan how much to eat, you need to know how much you burn. This calculator gives both halves of that: your basal metabolic rate, the energy your body spends at complete rest, and your total daily energy expenditure, which adds the movement of a normal day. The maintenance figure it produces is the calorie level that holds your weight where it is.
It offers three formulas because they suit different situations. Mifflin-St Jeor is the modern standard and the right default. Harris-Benedict is the older equation, still widely quoted, and reads slightly higher. Katch-McArdle takes a different route through your lean body mass, which makes it the most accurate when you know your body fat and the least when you do not. All five activity levels are shown together so you can see the range.
Everything is worked out in your browser, in metric or imperial, with nothing uploaded and no account. Remember that any calorie figure is an estimate: metabolism varies from person to person in ways a formula cannot see. Use this as a well-founded starting point, then adjust against what your weight actually does over the following weeks.
Frequently Asked Questions
What BMR and TDEE are, and which formula to trust.
BMR is the energy your body uses at complete rest, just to keep you alive. TDEE is that figure multiplied by an activity factor to include everything you do in a day. TDEE is the calorie level that maintains your weight; BMR is the floor beneath it.
Mifflin-St Jeor for most people; it is the most accurate general formula. Use Katch-McArdle only if you have a reliable body fat percent, since it works from lean mass. Harris-Benedict is the older standard and reads a little higher. The tool shows whichever you pick.
Because TDEE is BMR times that factor, and the factors step up in fairly large jumps. Moving from lightly to moderately active can add several hundred calories. Choose the level that matches a typical week honestly, and correct it against your real results.
No. It is a solid estimate based on population averages. Real metabolism varies with muscle, genetics, sleep and dieting history. Treat the figure as a starting point and let a few weeks of your own weight data refine it.
No. Everything is worked out in your browser, with history and saved setups on this device only. You can confirm it in the Network tab or by working offline.
