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Calorie calculator Ireland
Enter your sex, age, height, weight and how active you are to see how many calories you burn in a day — and what to eat to maintain, lose or gain weight.
- Mifflin-St Jeor equation, the one clinicians use
- Maintenance, loss and gain targets in one view
- Runs in your browser — nothing is sent or stored
Your daily calories
years
cm
kg
Light exercise 1–3 days a week
2,225kcal / day
Maintenance calories
What you burn on an average day at this activity level, everything included.
- Basal metabolic rate
- 1,618
- Lose about 0.25 kg a week
- 1,975
- Lose about 0.5 kg a week
- 1,725
- Gain about 0.25 kg a week
- 2,525
Estimates for healthy adults, and a screening tool rather than a diagnosis or a prescribed diet. Talk to a doctor before changing your intake if you are pregnant or breastfeeding, under 18, or being treated for any condition.
01
What your calorie numbers mean
The headline figure is your maintenance level: roughly what you burn in a day once your activity is counted in. Eat that much and your weight stays where it is.
The targets under it are the same figure with a deficit or a surplus applied. A 500 kcal daily deficit works out at about half a kilo a week, which is the rate most guidelines settle on — fast enough to notice, slow enough to keep.
Maintain
- Daily intake
- Your maintenance figure
- What to expect
- Weight holds steady over weeks, not days
Mild loss
- Daily intake
- Maintenance − 250 kcal
- What to expect
- About 0.25 kg a week
Steady loss
- Daily intake
- Maintenance − 500 kcal
- What to expect
- About 0.5 kg a week
Gain
- Daily intake
- Maintenance + 300 kcal
- What to expect
- About 0.25 kg a week, best paired with resistance training
02
Choosing your activity level
The activity multiplier is the biggest lever in this calculation: for the same body, the gap between sedentary and extremely active is more than 700 kcal a day. It covers everything you do, not just training — standing, walking, housework and your job all count.
Most people pick one level too high. If you train three times a week and sit for the rest of it, you are lightly to moderately active, not very active.
- Sedentary — a desk job and little or no deliberate exercise.
- Lightly active — light exercise or sport one to three days a week.
- Moderately active — moderate exercise three to five days a week.
- Very active — hard exercise six or seven days a week.
- Extremely active — a physically demanding job, or hard training twice a day.
03
How the calculation works
Your basal metabolic rate — what the body burns at complete rest — comes from the Mifflin-St Jeor equation: 10 × weight in kg, plus 6.25 × height in cm, minus 5 × age, then plus 5 for men or minus 161 for women.
That figure is multiplied by your activity level, from 1.2 for sedentary up to 1.9 for extremely active. The result is your total daily energy expenditure — the maintenance number at the top of the read-out.
Worked example: a 30-year-old man, 180 cm and 80 kg, has a basal rate of 1,780 kcal. Lightly active (× 1.375) that is about 2,448 kcal a day to maintain his weight.
04
What a calorie calculator cannot tell you
Every equation here is a population average fitted to measured data, and individuals sit either side of it. Treat the number as an estimate to test against the scales over three or four weeks, not as a fact about your body.
- Estimates are typically within about 10% for most adults — that is 200 kcal either way on a 2,000 kcal day.
- It says nothing about what those calories are made of, and protein, fibre and micronutrients decide whether a diet holds.
- Thyroid conditions, some medications and a long history of dieting all shift energy expenditure away from the estimate.
- It is not designed for children, for pregnancy or breastfeeding, or for athletes in heavy training blocks.
- Very muscular people are underestimated, because the equation uses total body weight rather than lean mass.
Where to go from here
A calorie figure is a starting point, not a plan. These are the consultations our doctors run for weight, nutrition and the checks a number cannot give you.
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Talk any result through with a registered doctor by video, and get the checks that BMI cannot give you.
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Calorie calculator — FAQs
How many calories should I eat a day?
Enough to match what you burn, if your weight is where you want it. For most adults that lands somewhere between 1,800 and 2,800 kcal, but the range is wide because it depends on your size, age and how active you are. The calculator above gives your own figure rather than the average.
How many calories do I need to eat to lose weight?
About 500 kcal a day below your maintenance figure gives roughly half a kilo a week, and 250 below gives about a quarter of a kilo. Bigger deficits do not reliably work faster — they are simply harder to keep, and more of the loss comes from muscle.
Is 1,200 calories a day safe?
It is the lowest intake this calculator will suggest, and it is a floor rather than a recommendation. Below roughly that level it becomes difficult to get enough protein, vitamins and minerals from food, so a lower intake should only be followed under medical supervision.
Which formula does this calorie calculator use?
Mifflin-St Jeor for the basal rate, then a standard activity multiplier. It replaced the older Harris-Benedict equation in most clinical use because it is more accurate for modern body compositions, typically to within about 10% for healthy adults.
Do I have to count calories to lose weight?
No. Counting is one method of holding a deficit, and plenty of people manage the same thing by changing what they eat rather than by weighing it. Knowing roughly where your maintenance level sits is useful either way, because it tells you how big a change you are actually making.
Does this calorie calculator store my details?
No. The calculation runs entirely in your browser. Nothing you type is sent to our servers or saved.
How many calories a day are recommended in Ireland?
The figure on Irish food labels is the EU reference intake of 2,000 kcal a day for an average adult, and the healthy eating guidelines are built around roughly 2,000 kcal for women and 2,500 for men. Those are population averages: your own maintenance figure depends on your height, weight, age and how active you are, which is what the calculator above estimates.
Can a doctor in Ireland review my calorie target?
Yes. A GP can check whether a target is sensible for your history and refer you to a dietitian if you need a full eating plan. Our Irish-registered doctors can review your figure by video alongside your blood pressure, cholesterol and blood glucose, which is what tells you whether the number is the thing worth changing.
Want a plan, not just a number?
Book a video consultation with a registered doctor and go through what the figure means for your weight, your bloods and your history.