Calorie Calculator
Your resting burn and your daily total, from the formula most dietitians use — together with an honest account of how approximate it is.
Read the range, not the number
The figure above looks precise and is not. The Mifflin-St Jeor formula — the one most dietitians reach for — lands within about ten per cent of a person's real resting burn most of the time. Most of the time, not always: it is built from averages, and it is furthest out for people who are very muscular, very tall, very small, or older.
That is why a range is shown beside the number. If the range is 2,100 to 2,600, then 2,350 is not your answer — the range is your answer, and anything inside it is consistent with what the formula knows about you, which is four numbers.
The activity multiplier is the weak link
The resting figure comes from a formula fitted to measurements. The step after it — multiply by 1.375 because you exercise lightly — is a rule of thumb, and it is the part that moves the answer most.
People also reliably pick a level above the one they live. An hour at the gym three times a week, with a desk job and a car, is closer to the light row than the moderate one. The ladder underneath shows every level at once so you can see how much the choice is worth: it is often four or five hundred calories between neighbouring rows, which is more than the formula's own error.
What to do with it
Treat it as a starting guess to test. Eat around that figure for two or three weeks, weigh yourself at the same time of day, and see what actually happens. Your body's answer beats the formula's, because it is measuring you rather than a population average.
Day-to-day weight swings of a kilo or two are water and food in transit, not fat. It takes a couple of weeks of readings before a trend means anything at all.
Two honest limits
The formula has only two variants, male and female, because that is how it was published and validated. That is a limit of a 1990 study, not a statement about people. If neither fits, the two results bracket a reasonable estimate — try both and read the span between them as the range.
This is arithmetic, not advice. It is a formula with your numbers in it. If you are pregnant or breastfeeding, managing diabetes, thyroid disease, an eating disorder or any condition that affects appetite or metabolism, or you are under about eighteen, the number on this page is not the one to plan from — a doctor or a registered dietitian is.
Frequently asked questions
How accurate is it?
Within roughly ten per cent of the real resting figure for most people, and further out for anyone whose body is far from the average the formula was built on. The daily total is less accurate still, because the activity multiplier is a rule of thumb rather than a measurement.
Which activity level should I choose?
Probably one lower than you first think. Nearly everyone picks too high. A desk job with three gym sessions a week is the light row, not the moderate one.
Why does it ask for male or female?
Because the published formula has exactly two variants and differs between them by 166 calories. That is a limit of the 1990 study it comes from. If neither fits you, calculate both and treat the gap between them as your range.
Should I eat this many calories to lose weight?
This page gives the figure for staying as you are, and deliberately does not prescribe a target. Deciding to eat less than you burn, and by how much, is worth doing with a doctor or a registered dietitian - particularly if you have any condition that affects appetite or metabolism.
Is my information sent anywhere?
No. Your age, weight and height are used by JavaScript in your own browser and are never uploaded or stored. Close the tab and they are gone.
Is my text sent anywhere?
No. Everything happens in JavaScript inside your own browser. Nothing is uploaded and nothing is saved - close the tab and it is gone.