Work out your macros in grams
Counting calories tells you how much to eat; counting macros — protein, carbohydrate and fat — tells you what that food should be made of. This macro calculator estimates your daily calorie needs from your age, sex, height, weight and activity, adjusts them for your goal, and splits the result into grams of each macronutrient per day and per meal.
Choose a ready-made split — balanced, dietary-guidelines style, low carb, high protein or keto — or drag the sliders to build your own. The sliders always add up to 100%, and a donut chart shows the balance at a glance. Already know your calorie target from a coach or app? Type it in and the calculator uses it instead.
The numbers are estimates for healthy adults, not medical advice. Anyone with diabetes, kidney disease or a history of disordered eating should plan macros with a doctor or registered dietitian.
How to use the Macro Calculator
- Choose metric or imperial units, select your sex and enter your age, height and weight.
- Pick your activity level and goal — or type your own calorie target to override the estimate.
- Choose a macro split from the list, or move the protein, carbs and fat sliders for a custom split.
- Select how many meals you eat a day, from 3 to 6.
- Read your daily grams and per-meal grams in the table, and check the protein-per-kilogram figure.
Macro Calculator features
Calories calculated for you
Uses the Mifflin-St Jeor equation and standard activity factors, with a ±250 or ±500 kcal adjustment for your goal.
Six split options
Balanced/Zone, dietary guidelines, low carb, high protein, keto and fully custom.
Sliders that always total 100%
Change one macro and the others adjust automatically, so you never end up with an impossible split.
Per-meal targets
Divide your daily grams across 3–6 meals to make planning and meal prep easier.
Donut chart and fibre target
See your calorie split visually, plus a fibre target of 14 g per 1,000 kcal.
How macros are calculated
Each macronutrient provides a fixed amount of energy, known as the Atwater factors: protein 4 kcal per gram, carbohydrate 4 kcal per gram and fat 9 kcal per gram (alcohol supplies 7 kcal/g). To turn a calorie target into grams, multiply it by each percentage and divide by these factors.
Example: a 30-year-old man, 180 cm and 80 kg, who is moderately active has a TDEE of about 2,759 kcal. With a balanced 30/40/30 split: protein = 2,759 × 0.30 ÷ 4 ≈ 207 g, carbs = 2,759 × 0.40 ÷ 4 ≈ 276 g, fat = 2,759 × 0.30 ÷ 9 ≈ 92 g. Over three meals that is about 69 g protein, 92 g carbs and 31 g fat each.
The calorie estimate comes from the same method as our calorie calculator; loss goals never go below 1,200 kcal (women) or 1,500 kcal (men).
Choosing a macro split
- Balanced / Zone (30/40/30): the ratio popularised by the Zone diet. Plenty of protein, moderate carbs — an easy default for active people.
- Dietary guidelines (20/50/30): sits in the middle of the Acceptable Macronutrient Distribution Ranges (AMDR) set by the US National Academies: protein 10–35%, carbs 45–65%, fat 20–35%.
- Low carb (35/25/40): fewer carbs and more fat and protein; some people find it easier to control appetite this way.
- High protein (40/30/30): useful when cutting calories while strength training, to help preserve muscle.
- Keto (20/5/75): very low carbohydrate, usually under 50 g a day, to encourage ketosis. It is restrictive and not suitable for everyone.
Keto, body recomposition and carb cycling modes
Keto: enter a net-carb limit in grams (net carbs calculator), your body-fat estimate and a protein target per kg of lean mass. Protein = g/kg × lean mass, carbs = your limit, and fat fills the remaining calories. Reviews describe ketogenic diets as roughly 20–50 g of carbohydrate a day (Paoli et al., Eur J Clin Nutr 2013;67:789–796); treat that as a commonly used range, not a prescription. If you have diabetes or take glucose-lowering medication, speak to your doctor before going low carb.
Body recomposition: a small deficit (10% below TDEE by default), protein at 2 g/kg body weight (the meta-analysis by Morton et al., Br J Sports Med 2018, found gains levelling off near 1.6 g/kg, with an upper estimate of 2.2), 25% of calories from fat and the rest from carbs. It is a rule of thumb, and recomposition works best for beginners, people returning to training and those carrying extra fat.
Carb cycling: choose how many high-carb and low-carb days you want; high and low days are set a chosen percentage above and below the medium day, scaled so the weekly average equals your calorie target. Protein stays constant and fat is 20%, 30% and 40% of calories on high, medium and low days. These are conventions, not clinically proven ratios.
Tips for hitting your macros
- Set protein first — around 1.6 g per kg of body weight suits most people who train. The protein calculator gives a target for your goal.
- Spread protein evenly across meals, and choose mostly whole-food carbohydrates to reach the fibre target.
- Within about 5 g of each target is close enough; consistency over weeks matters far more than daily precision.
Macro Calculator FAQ
What is the best macro split for weight loss?
Total calories matter most for weight loss. Within that, a higher protein intake (30–40% of calories, or about 1.6–2.2 g/kg) helps keep you full and protect muscle. Pick a carb and fat balance you can stick to.
How do I calculate macros by hand?
Multiply your daily calories by the percentage for each macro, then divide protein and carbs by 4 and fat by 9. For 2,000 kcal at 30/40/30, that is 150 g protein, 200 g carbs and about 67 g fat.
Are macros the same as calories?
No. Calories measure total energy; macros describe where that energy comes from. Two diets with the same calories can have very different amounts of protein, carbohydrate and fat.
How many carbs can I eat on keto?
Most ketogenic diets limit carbohydrate to roughly 20–50 g a day, which is about 5–10% of calories for most adults. The keto preset uses 5%.
Should I change my macros on rest days?
You can, but it isn’t necessary. Many people keep protein steady and shift some carbs from rest days to training days. Weekly totals matter more than day-to-day variation.
Is this macro calculator free and private?
Yes. It is free, needs no account and runs in your browser. Only your metric or imperial preference is stored on your device.