Macro Calculator guide
Macro Calculator: Daily Carbs, Protein and Fat in Grams
Use our macro calculator to work out your daily calories and split them into grams of carbohydrate, protein and fat for your goal.
By the AllCalculator editorial teamUpdated 16 October 20262 min read
Macronutrients, or macros, are the three nutrients that provide calories: carbohydrate, protein and fat. Counting them, rather than just calories, can help you build meals that support training, weight loss or muscle gain. Our Macro Calculator works out your targets in grams.
How to use the calculator (Macro Calculator)
- Enter your sex, age, weight and height.
- Choose your activity level and goal: lose, maintain or gain weight.
- Choose a macro split: balanced, higher protein or lower carb.
You'll see your daily calories and how many grams of each macro to eat, plus a table comparing all three splits.
How it works
The calculator first estimates your daily calorie needs with the Mifflin-St Jeor equation and your activity level. For weight loss, it takes off 500 kcal a day (about 0.5kg a week), and for weight gain it adds 250 kcal. It never goes below 1,200 kcal for women or 1,500 kcal for men.
Then it splits the calories by your chosen percentages and converts them to grams:
- Carbohydrate: 4 kcal per gram
- Protein: 4 kcal per gram
- Fat: 9 kcal per gram
The splits
| Split | Carbs | Protein | Fat |
|---|---|---|---|
| Balanced | 50% | 20% | 30% |
| Higher protein | 40% | 30% | 30% |
| Lower carb | 25% | 35% | 40% |
The balanced split is closest to UK healthy eating guidance, which suggests about half your energy from carbohydrate and no more than 35% from fat.
A worked example
With the calculator's default settings (a 35-year-old woman, 168cm, 70kg, light exercise, maintaining weight), daily needs are about 1,940 kcal. A balanced split gives about 243g carbs, 97g protein and 65g fat.
Frequently asked questions
Which split is best?
The one you can stick to. For weight loss, total calories matter most. Higher protein can help you feel full and keep muscle while losing weight.
Do I need to hit my macros exactly?
No. Being within 5 to 10g most days is plenty for most people.
Is a low-carb diet safe?
It can be for many people, but if you have diabetes or take medicines that lower blood sugar, speak to your GP or diabetes team first.
For more detail on each nutrient, see our Protein Calculator, Carbohydrate Calculator and Fat Intake Calculator.
Sources and further reading
- NHS: The Eatwell Guidenhs.uk
- NHS: Understanding caloriesnhs.uk
- GOV.UK: SACN carbohydrates and health reportgov.uk
Links open official and independent websites in a new tab.
This guide is general information to help you understand your options. It isn't financial, tax, legal or building advice and doesn't take your personal circumstances into account. Figures were checked when the guide was last updated and can change, so confirm anything important with GOV.UK, HMRC, a regulated adviser or a qualified tradesperson.