Calorie Calculator

Most of your energy goes on doing nothing

The single most counterintuitive fact in energy balance is how dominant the resting component is. For a typical person, basal metabolic rate accounts for something like 60 to 70 percent of total daily energy expenditure — the energy spent keeping your heart beating, your brain running, your body at temperature and your cells maintained, entirely irrespective of whether you get out of bed. Deliberate exercise, for most people, is a surprisingly small slice: a hard hour in the gym might add a few hundred calories, which a single generous snack undoes. This is why exercise alone is a weak weight-loss lever and a superb health one, and why the arithmetic of weight change is dominated by what is eaten rather than by what is burned.

Why the calculator's number is only a starting point

Every TDEE formula is a regression fitted to a population, which means it describes the average person with your height, weight, age and sex — and nobody is the average person. Real metabolic rates vary meaningfully between individuals with identical inputs, thanks to differences in muscle mass, thyroid function, genetics and how much you fidget. On top of that, the activity multiplier is a self-assessment, and people are famously poor at estimating both how much they move and how much they eat. So the sensible use of the number is empirical: adopt it as a hypothesis, hold it for a few weeks, weigh yourself consistently, and let the trend tell you whether the estimate was right for you. The scale is a better guide to your metabolism than any equation.

This is an estimate, not medical advice

A calculator works from a formula and a handful of numbers, and a formula cannot examine you. The results here are population-level estimates derived from studies of large groups, and any individual can sit far from the average for entirely healthy reasons. They are a useful starting point for a conversation and a reasonable way to track a trend over time, but they are not a diagnosis and they cannot account for your medical history, medication, body composition or anything else a clinician would consider. If a result concerns you, or if you are making a decision about your health, speak to a doctor rather than to a web page.