Calorie Calculator
Daily calories to maintain, lose or gain, with every activity level charted side by side.
- Resting (BMR)
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- To lose 0.5 kg a week
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- To gain 0.5 kg a week
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Free forever, no sign-up and no limits, and this tool installs on its own so you can keep it on your home screen.
Your resting metabolic rate and daily calorie needs, with all five activity levels charted side by side rather than hidden behind a dropdown. It uses the Mifflin St Jeor equation, which is the one most dietitians now prefer, and shows what to eat to hold steady, lose or gain.
How to use it
- Enter your detailsSex, age, height and weight, in metric or imperial.
- Compare the levelsThe chart shows all five activity levels at once, so you can see how much the choice is worth.
- Read the targetsMaintenance is the headline, with the figures for losing or gaining half a kilogram a week underneath.
The dropdown problem
Every calculator in this space asks you to pick an activity level from a list, prints one number, and moves on. The trouble is that the labels are vague and the difference between them is enormous: sedentary to moderate is about a third more food. If you guess wrong you have a target that is out by more than the deficit you were aiming for.
Charting all five removes the guess from the critical path. You can see that the honest answer is probably between two of them, and that a day in the office and a day of hiking are not the same week.
What the number actually is
An estimate of energy out, based on your size, from an equation fitted to a few hundred people in a lab. It does not know your thyroid, your sleep, how much you fidget, or how efficiently you absorb what you eat. Individual variation around these equations runs to about ten percent in either direction, which is two or three hundred calories for most adults.
The practical consequence is that the number is a starting point, not a prescription. Eat to it for a fortnight, watch the scale, and adjust. The equation gets you close enough that the adjustment is small.
Why Mifflin St Jeor and not Harris Benedict
Harris Benedict dates from 1919 and was revised in 1984, and it tends to overestimate for modern body compositions. Mifflin St Jeor was derived from a larger and more representative sample and has performed better in comparison studies since. Where a tool does not say which equation it used, it is usually Harris Benedict, and that is worth knowing when two calculators disagree by a hundred calories.
What this will not do
It will not build you a diet, count macros, or tell you what to eat. It will not adjust for medical conditions or medication, both of which can move the number substantially. And it stops short of very low targets, because those are a clinical decision rather than a calculator's.
Questions people ask
Which formula does this use?
Mifflin St Jeor, published in 1990. It replaced Harris Benedict as the default in most clinical practice because it is more accurate for modern populations, typically within about ten percent for people who are not at the extremes of body composition.
What is the difference between BMR and TDEE?
BMR is what your body burns doing nothing at all: keeping you warm, breathing, running your organs. Total daily energy expenditure is that plus everything else, including fidgeting, walking to the kitchen and any actual exercise. TDEE is the number that matters for eating; BMR is roughly sixty to seventy percent of it.
Why show all five activity levels?
Because almost nobody knows which one they are, and the gap between them is large. Going from a desk job to moderate activity is worth several hundred calories a day, which is more than most people's deficit. Seeing them together makes the choice visible instead of asking you to commit to a label you cannot verify.
How many calories to lose weight?
A deficit of about 500 a day is the usual starting point, and corresponds to roughly half a kilogram a week. That is the figure shown. Larger deficits are harder to hold and lose more muscle, and going below about 1,200 a day is not something to do without medical supervision.
Why does the estimate not match my fitness tracker?
Trackers measure movement and estimate energy from it, often generously, and they usually add exercise on top of a baseline that already includes some. Equations like this one estimate from body size instead. Both are approximations, and if you are tracking intake against either, the useful signal is your weight over a few weeks rather than the daily number.
Does age really change it that much?
Some, and less dramatically than people assume. The formula subtracts five calories per year of age, so a decade is fifty calories a day. The larger age effect in real life is usually lost muscle and less movement rather than the metabolism itself slowing sharply.
Should I eat back exercise calories?
If your activity level already reflects your training, no, that would double count it. The five levels here are meant to include your usual exercise, which is why the chart is the interface rather than a separate exercise field.