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Log it, macros fill in.
Scan a UK barcode or search. Protein, carbs and fat come straight off the UK panel.
gThe UK macro calculator
Macro calculator. Protein, carbs and fat in grams.
Type your stats and goal. We work out your daily calories, then split them into protein from your body weight, fat at about a quarter, and carbohydrate for the rest.
Sex
Age (years)
Height
Weight
Activity level
Goal
Protein is set from your body weight; fat takes about a quarter of calories; carbs fill the rest.
01Past the numbers
Macros are easy
to set, harder to hit.
Three numbers on a screen are the simple part. Hitting them across real meals is where it gets fiddly. NutraSafe counts protein, carbs and fat on every food you log, scanned from a UK barcode, against the targets you set here, and reads the additives on the pack while it's at it.
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Three bars, one glance.
Protein, carbs and fat against your targets, updating as the day goes, so you know what's left for dinner.
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Protein front and centre.
The macro that matters most for holding muscle, tracked first, with the others alongside.
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Vitamins too.
14 vitamins and 13 minerals against the UK NRV, so chasing macros doesn't cost you the micros.
02How the split works
Where the
grams come from.
Calories first, then protein from your body weight, then fat and carbohydrate fill what's left.
Calories for your goal
Your TDEE from Mifflin-St Jeor, then a 500 deficit to lose, a 300 surplus to build, or unchanged to maintain.
cal = TDEE − 500 (to lose)Protein from body weight
About 1.8g per kilogram, the middle of the 1.6 to 2.2g range tied to holding muscle. Protein is 4 calories a gram.
protein g = 1.8 × kgFat at a quarter
Roughly 25 per cent of your calories, enough for hormones and to keep food satisfying. Fat is 9 calories a gram.
fat g = (0.25 × cal) / 9Carbs fill the rest
Whatever calories are left after protein and fat go to carbohydrate, your main training fuel. Carbohydrate is 4 calories a gram.
carb g = remaining cal / 403Frequently asked
Questions
people ask.
Answers grounded in the standard energy and protein maths.
What are macros?
Macros, short for macronutrients, are the three nutrients that give food its energy: protein, carbohydrate and fat. Protein and carbohydrate provide 4 calories per gram, fat provides 9. Your calorie total decides whether you gain or lose weight; your macro split shapes how you feel and, with enough protein, how much of any loss is fat rather than muscle.
How do I calculate my macros?
Start with your daily calories (your TDEE, adjusted for your goal). Set protein from your body weight, around 1.8g per kilogram. Set fat to about a quarter of your calories. Fill the rest with carbohydrate. The calculator does all of this from your height, weight, age, activity and goal.
How much protein do I need?
For general health the reference is lower, but if you are training or in a calorie deficit, most evidence points to 1.6 to 2.2g of protein per kilogram of body weight a day to hold on to muscle. This calculator uses 1.8g per kilogram as a sensible middle. Spread it across your meals rather than one big hit.
What is the best macro split?
There is no single best split. Protein is the one worth setting deliberately; carbohydrate and fat can flex to your preference and how you train. A common starting point is protein from body weight, fat at about 25 per cent of calories, and carbohydrate filling the rest. Adjust based on energy, hunger and performance.
Do I have to hit my macros exactly?
No. Treat them as targets, not pass-or-fail lines. Getting protein and total calories close most days does the heavy lifting. The split between carbohydrate and fat has more room to move. Tracking for a few weeks builds the instinct, then you can ease off the precise logging.
Aaron Keen is the founder of NutraSafe. He built this calculator on the Mifflin-St Jeor equation and the protein ranges from the sports-nutrition literature, and checks the figures himself. About the research →
You've got the macros.
Now hit them.
Get NutraSafe on the App Store →
Free to download. The food log, the additive flags and 25 entries a day are free. Pro is £3.99 a month or £34.99 a year for unlimited logs, macro and vitamin tracking, AI Coach, workouts and fasting.
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