Enter your measurements, activity and goal: the tool returns your daily expenditure, a target intake as a range, and the split across protein, fat and carbohydrate.
Why this tool shows a range
Every calorie calculator on the internet gives you a single number, down to the digit. It is reassuring, and it is false.
They all rest on predictive equations — here Mifflin-St Jeor, the least bad on a general population. Those equations carry roughly 10% error on any given individual. For an estimated 2,600 kcal expenditure, the real figure sits somewhere between 2,340 and 2,860. Printing "2,613 kcal" implies a precision the method cannot deliver.
Two people of the same height, weight, age and stated activity can differ by 400 kcal a day. That gap comes from lean mass, genetics and non-exercise activity — everything the form does not ask and cannot ask.
What the formula cannot know
- Your lean mass. It drives most of your basal rate, and body weight alone says nothing about it.
- How much you move without noticing. Walking, fidgeting, taking the stairs: this varies by several hundred calories between two people.
- Your history. After months of restriction, expenditure adapts downward beyond what weight loss explains.
- What you actually eat. Portion estimates run low, systematically, including among careful people.
The only thing that settles it
The formula is a starting point, not an answer. The answer is the scale and the mirror over three weeks.
- Hold the central estimate for three full weeks. Two is not enough — water shifts hide the trend.
- Weigh yourself at the same time, several times a week, and compare weekly averages only. Never two isolated readings.
- Compare what actually happened against the expected change the tool shows.
- Adjust by 150 to 200 kcal in the right direction. Then wait another three weeks.
It is slow, and that is exactly why it works: you end up knowing your real number, the one no equation could have given you.
How the macros are split
The priority order is settled. Protein first, because it protects muscle and satisfies most. Fat next, with a floor around 0.8 g/kg for hormonal function. Carbohydrates take what remains — and they are what fuels intensity in the gym.
That remainder is not a rounding error: it is the fuel for your heavy sets. A cut run too low on carbohydrate almost always shows up as collapsing loads.
Related
- Protein calculator — refine the protein share by age and build.
- Volume calculator — the stimulus, without which calories build nothing.
- Why you are not gaining muscle — when the number is not the problem.
Frequently asked questions
How do I calculate calories for bulking?
Estimate your daily expenditure, then add 10 to 15%. A larger surplus does not build muscle faster; it mostly increases the fat you gain alongside. The metric that matters is rate of weight gain — aim for 0.25 to 0.5% of body weight per week.
What calorie deficit loses fat without losing muscle?
A deficit of 15 to 20% of daily expenditure, paired with high protein and loads that do not drop in the gym. More aggressive deficits speed up weight loss but markedly increase the share of it that comes from muscle.
Why does your calculator give a range instead of an exact number?
Because predictive equations carry about 10% error on any individual. A single figure implies a precision that does not exist. The range is honest, and the three-week measurement is what gives you your actual number.
Should I eat more on training days?
Not necessarily. The body does not settle up daily: weekly totals drive weight change. Redistributing intake can be convenient, but it confers no measurable advantage.
Basal metabolic rate or total expenditure — which should I use?
Total expenditure. Basal rate is what you would burn lying still all day; it only serves as a building block. Total expenditure, activity included, is the figure to set goals against.