Type in the number of calories you eat or plan to eat in a day, and the macro calculator splits it into practical gram ranges for carbohydrate, fat, protein and fibre.
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Key points
- Macros are the three nutrients that supply energy: carbohydrate and protein give about 4 kcal per gram, fat about 9 kcal per gram.
- The calculator shows ranges, not one magic number: 45–60% of your calories from carbohydrate, 25–35% from fat and 15–25% from protein.
- Fibre gets its own line: at least 25 g a day, or more if you eat more calories.
- Add your height for a protein guide based on 0.83 to 1.2 g per kg of a healthy reference weight, so the number stays realistic in a larger body.
- For weight loss, the total matters more than the split. Pick a balance you enjoy, with enough protein and plenty of fibre.
How to use the macro calculator
Unlike most macro tools, this one does not ask for your weight, age or activity. It starts from a calorie figure you already have.
- Find your daily calories. Use the calorie calculator for a maintenance figure, or the calorie deficit calculator for a weight-loss target. Any number between 1,000 and 5,000 kcal works.
- Enter it in the first box. Round numbers are fine; 1,800 is as useful as 1,812.
- Optionally, add your height. Choose metric or imperial units first. Height is only used for the protein guide.
- Press Calculate. The gram ranges appear below the form, rounded to whole grams.
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What each line of the result means
| Line in the result | Share of calories | How grams are worked out |
|---|---|---|
| Carbohydrates | 45–60% | Calories × share ÷ 4 |
| Fat | 25–35% | Calories × share ÷ 9 |
| Protein | 15–25% | Calories × share ÷ 4 |
| Fibre (at least) | Not a share | 14 g per 1,000 kcal, never less than 25 g |
| Protein guide by height | Not a share | Weight at BMI 25 for your height × 0.83 to 1.2 g |
The three energy ranges overlap on purpose. You cannot be at the top of all three at once; if you eat more carbohydrate, you will naturally eat a little less fat or protein, and the total still adds up.
An example at 1,800 kcal
Suppose your weight-loss target is 1,800 kcal a day and you are 165 cm tall. This is what the calculator shows.
| Nutrient | Daily range |
|---|---|
| Carbohydrates | 203 – 270 g |
| Fat | 50 – 70 g |
| Protein | 68 – 113 g |
| Fibre | at least 25 g |
| Protein guide by height | 56 – 82 g |
Notice that the protein guide by height (56–82 g) sits at the lower end of the percentage range (68–113 g). A sensible aim here is somewhere around 70 to 90 g a day, spread across your meals.
At 2,200 kcal, the ranges grow accordingly: about 248–330 g of carbohydrate, 61–86 g of fat, 83–138 g of protein, and a fibre target that rises to about 31 g.
Where do the macro ranges come from?
The ranges are based on dietary reference values set by expert bodies in Europe and the United States. They describe intakes that support long-term health in the general adult population.
| Nutrient | EFSA (Europe) | US acceptable ranges (AMDR) | This calculator |
|---|---|---|---|
| Carbohydrate | 45–60% of energy | 45–65% of energy | 45–60% |
| Fat | 20–35% of energy | 20–35% of energy | 25–35% |
| Protein | 0.83 g per kg body weight | 10–35% of energy | 15–25%, plus a guide by height |
| Fibre | 25 g a day | 14 g per 1,000 kcal | The higher of the two |
European reference values
The European Food Safety Authority (EFSA) has published scientific opinions on carbohydrates, fibre, fats and protein. For carbohydrate, EFSA set a range of 45 to 60% of total energy for adults and children. It considered 25 g of fibre a day adequate for normal bowel function in adults.
For fat, EFSA advised 20 to 35% of energy. Our calculator starts at 25%, a slightly narrower band that leaves room for oily fish, nuts, seeds and plant oils while keeping meals satisfying.
For protein, EFSA set a population reference intake of 0.83 g per kg of body weight per day for adults, a level meant to cover the needs of nearly everyone in a healthy population.
United States reference values
The US Dietary Reference Intakes include acceptable macronutrient distribution ranges, or AMDRs: 45–65% of energy from carbohydrate, 20–35% from fat and 10–35% from protein for adults. The National Academies recently published a letter report reviewing how these ranges should be updated in future.
The US adequate intake for fibre is based on 14 g per 1,000 kcal. That is why the fibre line in our calculator rises above 25 g once you enter more than about 1,800 kcal.
The current Dietary Guidelines for Americans, released in January 2026, suggest a higher protein range of 1.2 to 1.6 g per kg of body weight per day, while the RDA itself stays at 0.8 g per kg. They also keep the advice to limit saturated fat to less than 10% of daily calories and to cut down on added sugars.
Our calculator keeps to the more cautious European protein starting point, worked out from a reference weight.
Why the protein range sits at 15–25%
The full US range of 10–35% is very wide. At lower calorie intakes, 10% can fall short of what the body needs, especially during weight loss.
The middle band of 15–25% gives enough protein to help keep muscle and stay full, without pushing other foods, such as vegetables and whole grains, off the plate.
Protein by height: why a reference weight?
Most protein calculators multiply your current weight by a fixed number. In a larger body, that gives figures of 150 g or more that are hard to eat and often more than the body uses.
Protein is needed mainly for muscle, organs, skin, enzymes and the immune system. Fat tissue needs relatively little. So we use the weight at a BMI of 25 for your height as a reference, a practical approach also used in many clinics.
| Height | Reference weight | Protein per day |
|---|---|---|
| 155 cm | 60 kg | 50 – 72 g |
| 165 cm | 68 kg | 56 – 82 g |
| 175 cm | 77 kg | 64 – 92 g |
| 185 cm | 86 kg | 71 – 103 g |
The lower end, 0.83 g per kg, is the European reference intake. The upper end, 1.2 g per kg, reflects advice for older adults: the PROT-AGE study group recommended 1.0 to 1.2 g per kg a day for healthy people over 65 to help maintain muscle.
During weight loss, many dietitians aim for the upper half of this range, together with strength exercise. If you are very active or recovering from illness, your needs may be higher still; ask a dietitian.
Are you getting enough fibre?
Most adults eat less fibre than recommended. That is a pity, because fibre helps you feel full, supports regular bowel movements and feeds helpful gut bacteria.
A series of systematic reviews in The Lancet, led by Andrew Reynolds, linked higher fibre intakes with lower rates of heart disease, stroke, type 2 diabetes and bowel cancer. The greatest benefits were seen at about 25 to 29 g a day or more.
Good sources include vegetables, fruit with the skin, pulses such as lentils and beans, oats, wholegrain bread and pasta, brown rice, nuts and seeds. Build up slowly over a few weeks and drink enough fluids, or your gut may protest with bloating.
Macros for weight loss: does the split matter?
For weight loss, the evidence points to total calories and long-term consistency, not a precise ratio. A trial in the New England Journal of Medicine followed 811 adults on four reduced-calorie diets that ranged from 35% to 65% carbohydrate and from 20% to 40% fat.
After six months, people on every diet had lost on average about 6 kg. After two years, the differences between the diets were small and not significant. The authors concluded that reduced-calorie diets lead to meaningful weight loss whichever macronutrient they emphasise.
The practical message is freeing. You can choose a style of eating that suits your culture, budget and taste, as long as it fits within sensible ranges and you can keep it up.
Quality counts as much as quantity
Two plates with identical macros can be very different for your health. Carbohydrate from lentils, oats and vegetables brings fibre and vitamins; carbohydrate from sweets and soft drinks brings mostly sugar.
- Carbohydrate: choose whole grains, pulses, vegetables and fruit most of the time; keep sugary drinks and sweets for occasional treats.
- Fat: favour olive and rapeseed oil, nuts, seeds and oily fish; limit butter, fatty meat, pastries and fried snacks, which are high in saturated fat.
- Protein: mix plant sources (beans, lentils, tofu, nuts) with fish, eggs, dairy and lean meat; limit processed meats.
From grams to a real plate
Few people want to weigh every meal. These rules of thumb get you close to the calculator’s ranges without scales.
- At each main meal: half the plate vegetables or salad, a quarter a protein food, a quarter whole grains or potatoes.
- A palm-sized portion of fish, chicken, tofu or a generous spoonful of beans or lentils covers a good share of a meal’s protein.
- A thumb of fat per meal, such as a little oil for cooking or a few nuts, is usually enough.
- Breakfast: add protein and fibre together, for example oats with yoghurt and fruit, or wholegrain bread with egg.
Our free 7-day eating plan puts these ideas into a full week of meals and snacks.
Spread protein over the day
Many people eat little protein at breakfast and lunch, then most of it at dinner. Spreading it more evenly over three meals is an easy habit that helps you stay full between meals.
If your aim is about 80 g a day, think of it as roughly 20 to 30 g at each main meal, with the rest coming from snacks such as yoghurt, milk or a handful of nuts. You do not need protein shakes or bars to get there; ordinary food does the job, and it brings fibre, vitamins and minerals along with the protein.
Using food labels
Food labels list carbohydrate, fat, protein and often fibre per 100 g and sometimes per portion. Comparing two similar products per 100 g is the quickest way to spot the one with more fibre or less sugar and saturated fat.
Look at the portion you actually eat, not the portion printed on the pack. A bowl of cereal poured at home is often larger than the suggested serving.
Adjusting the balance over time
Start in the middle of each range for two or three weeks and notice how you feel. If you are hungry an hour after meals, try a little more protein and fibre; if meals feel heavy, try a little less fat.
When your calorie target changes, for example after losing a few kilos, run the calculator again with the new number. The percentages stay the same, but the grams shift with your energy needs.
Limits: when to get personal advice
The ranges are designed for healthy adults. They are a sensible default, but some situations call for different numbers.
- Kidney disease. People with reduced kidney function may need to limit protein. Do not raise your protein intake without checking with your doctor.
- Diabetes. How carbohydrate is spread across the day matters, especially with insulin or tablets that can cause hypos. A sharp cut in carbohydrate can mean your medication needs adjusting.
- Pregnancy and breastfeeding. Protein and energy needs rise. Follow your midwife or doctor, and do not use this tool to diet while pregnant.
- Eating disorders. Tracking grams can feed unhelpful patterns. If food and numbers take up a lot of your thoughts, talk to someone you trust and to your doctor.
- Athletes and heavy manual work. High training loads can increase carbohydrate and protein needs.
- Children and teenagers. Their needs differ; this tool is for adults.
These are general reference ranges for adults, not a personal diet prescription. A registered dietitian can tailor protein, carbohydrate and fibre to your health, medicines and preferences.
What to do next
Numbers only help when they lead to meals you enjoy and habits you can keep. Pick one small change this week rather than overhauling everything at once.
If you live with diabetes or kidney disease, or take regular medicines, talk to your doctor first before you change the balance of your meals.
A good first step is to add a protein food and a portion of vegetables to the meal where you usually have neither. A second step might be swapping white bread or rice for a wholegrain version a few times a week.
Movement makes your food work harder for you. Daily walking helps with blood sugar and appetite, and the free Start workouts include gentle strength exercises that help your body use protein to keep muscle.
If you would like help fitting this into your life, book a free video meeting (in English) with us. A free Obesity Foundation Club account brings the eating plan, workouts and calculators together, without any subscription.
Related calculators
- Calorie calculator: your maintenance calories, the number to start from.
- Calorie deficit calculator: a daily target for gentle weight loss.
- Water intake calculator: how much to drink, especially as you eat more fibre.
Frequently asked questions
What are the best macros for weight loss?
There is no single best split. A large two-year trial compared diets with very different amounts of fat, protein and carbohydrate and found similar weight loss on all of them, as long as calories were reduced. Choose a balance within the healthy ranges that you enjoy and can keep up, with enough protein and fibre.
How much protein do I need per day?
The European population reference intake for adults is 0.83 g of protein per kg of body weight per day. Older adults and people who are losing weight or doing strength exercise may benefit from a little more, around 1.0 to 1.2 g per kg. If you have kidney disease, ask your doctor before eating more protein.
Why does the calculator use my height instead of my weight for protein?
Protein needs depend mostly on muscle and other lean tissue, not on fat tissue. In a larger body, multiplying by total weight can give an unrealistically high number. Using a reference weight for your height keeps the guide practical; a dietitian can personalise it further.
How much fibre should I eat a day?
European advice considers 25 g a day adequate for normal bowel function in adults, and US guidance links fibre to energy intake at about 14 g per 1,000 kcal. Research suggests that eating 25 to 29 g or more a day is linked with lower risk of heart disease, type 2 diabetes and bowel cancer. Increase fibre gradually and drink enough water.
Do I have to count macros?
No. Macros are a way to understand the balance of your meals, not a rule you must track every day. Many people simply aim for a protein food at each meal, plenty of vegetables and whole grains, and fewer sugary and fatty snacks.
Is a low-carb diet better for people living with obesity?
Low-carbohydrate diets can work for people who find them easy to follow, but trials show that, over the long term, weight loss is similar to other reduced-calorie diets. If you use diabetes medicines, cutting carbohydrates sharply can cause low blood sugar, so talk to your doctor first.
Sources
- EFSA Panel on Dietetic Products, Nutrition and Allergies – Scientific opinion on dietary reference values for carbohydrates and dietary fibre. EFSA Journal (2010)
- EFSA Panel on Dietetic Products, Nutrition and Allergies – Scientific opinion on dietary reference values for fats. EFSA Journal (2010)
- EFSA Panel on Dietetic Products, Nutrition and Allergies – Scientific opinion on dietary reference values for protein. EFSA Journal (2012)
- National Academies of Sciences, Engineering, and Medicine – Rethinking the Acceptable Macronutrient Distribution Range for the 21st Century: a letter report (2024)
- US Office of Disease Prevention and Health Promotion – 2015 Dietary Guidelines Advisory Report, Appendix E-3.1, Table A4 (nutritional goals, fibre 14 g per 1,000 kcal)
- Oklahoma State University Extension – The new Dietary Guidelines for Americans 2025–2030 (2026)
- Reynolds A, Mann J, Cummings J, et al. – Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet (2019)
- Bauer J, et al. – Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group (2013)
- Sacks FM, et al. – Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. New England Journal of Medicine (2009)