Macro Calculator
Work out how many calories and macros you need for your goal — whether that's losing fat, building muscle, or holding steady. It takes thirty seconds, and the numbers are the same ones we use to build your meal plan.
Fill in the six fields above and your targets will appear here.
How your calories are calculated
Every figure above starts with the Mifflin-St Jeor equation, which estimates how many calories your body burns at complete rest from your weight, height, age and sex. It is the formula most dietitians reach for first, because it has held up better against measured data than the older equations it replaced.
That resting figure is then multiplied by how much you move:
| Activity level | Multiplier | Roughly |
|---|---|---|
| Sedentary | ×1.2 | Desk job, little to no exercise |
| Lightly active | ×1.375 | 1–3 days of exercise per week |
| Moderately active | ×1.55 | 3–5 days of exercise per week |
| Very active | ×1.725 | 6–7 days of hard exercise per week |
The result is your maintenance level — eat that and your weight stays roughly where it is. Your goal then adjusts it: losing weight takes 500 kcal off, which works out at about half a kilo a week; gaining muscle adds 300; sport performance adds 10%, because fuelling training is a different job from building a surplus. Maintaining leaves it where it is. There is also a sensible minimum built in, so the maths can never hand you a target too low to eat well on.
What each macro actually does
Protein. Set from your body weight rather than your calorie total — 1.6 g per kilo for most goals, 2 g if you are building muscle, 1.8 g for sport. It is what protects muscle while you lose fat, and it is the one most people are short on.
Fat. Takes a quarter of your calories. Much below that and hormone production and the absorption of vitamins A, D, E and K start to suffer, so we treat it as a floor worth respecting rather than a number to drive down.
Carbohydrate. Gets whatever calories are left once protein and fat are set. That is not an afterthought — carbs are the most flexible of the three, which makes them the right place to absorb the difference between a training day and a rest day.
Why this is a starting point, not a rule
These equations describe an average person with your measurements, and nobody is the average person. Two people of identical height, weight, age and training history can differ by a few hundred calories a day in what they actually burn. Nothing you can type into a form will resolve that.
So treat the number as a hypothesis rather than a verdict. Eat to it for a fortnight, weigh yourself a few times a week at the same time of day, and let what happens on the scale correct the estimate. Real data about you beats a better formula about people in general, every time.
What happens when real life gets in the way
Correcting that estimate week after week is the part a calculator cannot do for you, and it is the part that decides whether any of this works. Inside the app we compare what you actually logged against what the week called for, then re-portion the days that are left — so a big Saturday does not have to be paid back all at once on Sunday, and a quiet week is not wasted.
Your targets move with you, too: as your weight changes, so does the maintenance figure underneath them. The number above is where you begin. The adjusting is the work, and it is the bit we take off your hands.
Frequently asked questions
How accurate is a macro calculator?
Accurate enough to start with, not accurate enough to finish with. The Mifflin-St Jeor equation lands within about 10% of measured resting metabolism for most people, and the activity multiplier is the looser half of the sum — how much you actually move in a day is genuinely hard to estimate, including for you. So expect your true maintenance to sit a couple of hundred calories either side of the figure here. That is not a flaw in the maths; it is why the number is a starting point you then correct with real weigh-ins.
Should I eat the same macros every day?
You do not have to, and most people find it easier not to. Your body does not settle its books at midnight, so hitting your targets as a weekly total works just as well as hitting them daily. Eating a little less on quiet days to leave room for a dinner out on Friday is a strategy, not a failure. What matters is that the week adds up.
What happens if I go over my macros?
One day over is close to a rounding error against a week, and nothing you ate yesterday has undone your progress. What derails people is rarely the overshoot itself — it is deciding the week is already ruined and abandoning the rest of it. Note it, carry on, and let the following days absorb it.
Do I need to weigh my food?
For the first couple of weeks it helps more than almost anything else you could do, because it recalibrates your eye. Most portions people guess at are out by more than they would believe, particularly oils, nut butters, cheese, and rice or pasta weighed after cooking rather than before. After that, most people keep weighing the handful of things that are easy to misjudge and estimate the rest.
How often should I recalculate?
Every four to six kilos of change, or whenever your training load shifts meaningfully. Your resting burn falls as you get lighter — a smaller body costs less to run — which is the real reason progress that was steady for two months quietly stalls in the third. Recalculating is not starting over; it is updating the estimate to the person you are now.
Recipes that hit these numbers, planned for you
Set your goal once and get a week of real food built around it, adjusted as you go.
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