Macro Calculator — Protein, Carbs & Fat Targets
Fine-tune your performance. Calculate your optimal protein, fat, and carbohydrate intake based on your body composition and training volume.
Your Parameters
analytics Calculated Breakdown
Meal Distribution
4 MEALS| Meal | Protein (g) | Carbs (g) | Fats (g) |
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Macro Breakdown Guide
Protein (4 kcal/g)
Essential for muscle repair. Target 1.6–2.2g per kg of body weight for optimal performance.
Carbohydrates (4 kcal/g)
Primary fuel for high-intensity training. Adjust based on activity—higher for athletes.
Fats (9 kcal/g)
Vital for hormone production. Maintain at least 0.5–1g per kg of body weight.
Strategy Adjustments
Prioritize higher carbohydrate intake to fuel surplus training. Keep protein consistent and moderate fat.
Increase protein slightly to preserve lean muscle in a deficit. Reduce fats and carbs while prioritizing fiber.
How to Use This Macro Calculator
Getting accurate macro targets takes less than a minute. Here is what each input does and why it matters:
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1
Sex. Men and women have different baseline metabolic rates due to differences in body composition and hormonal profiles. Selecting your sex ensures the TDEE formula (Mifflin–St Jeor) uses the correct coefficients.
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2
Age. Basal metabolic rate declines roughly 1–2% per decade after age 20 due to shifts in muscle mass and hormonal output. The Mifflin–St Jeor equation accounts for this directly.
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3
Height and Weight. These two inputs define your body size and are the primary drivers of your BMR. Weigh yourself first thing in the morning (fasted, no clothes) for the most reproducible number.
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4
Activity Level. This is the most commonly misjudged input. Most people overestimate their activity level by one category. "Sedentary" applies if your job is desk-based and you do no formal exercise. "Lightly active" covers 1–3 sessions of moderate exercise per week. When in doubt, choose the lower option — you can adjust based on results.
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Goal. The calculator applies evidence-based adjustments: a 500 kcal deficit for fat loss (targeting ~0.5 kg/week), maintenance for body recomposition, and a 250–500 kcal surplus for muscle gain. The macro ratios shift to match each goal, with protein increasing during a deficit to protect lean mass.
Your calculated targets are a starting point, not a final prescription. If your weight is not changing after 2–3 weeks, adjust your calorie intake by 100–150 kcal in the appropriate direction. Formulas can be off by 10–15% for any individual due to metabolic variation.
What Are Macronutrients?
Macronutrients are the three classes of compounds that provide the body with calories: protein, carbohydrates, and fat. Unlike micronutrients (vitamins and minerals), which are needed in small amounts for regulatory functions, macronutrients are the raw fuel and structural material your body runs on. Every calorie you consume comes from one of these three sources.
Protein
Protein provides 4 kcal per gram and is the body's primary structural material — the building block of muscle, tendons, enzymes, antibodies, and hormones. It is composed of amino acids, 9 of which are "essential" (the body cannot synthesise them and must obtain them from food).
For muscle growth and retention, research consistently supports 1.6–2.2g per kg of bodyweight per day for active individuals. Sedentary adults need at least 0.8g/kg. Protein is the most satiating macronutrient, meaning it keeps you fuller per calorie than carbs or fat — a significant advantage when in a calorie deficit.
Best sources: chicken, fish, eggs, Greek yogurt, cottage cheese, tofu, legumes, lean beef.
Carbohydrates
Carbohydrates also provide 4 kcal per gram and are the body's preferred fuel for high-intensity exercise. Glucose — the simplest carbohydrate — is stored in muscles and the liver as glycogen, which is rapidly mobilised during intense training. When glycogen is depleted, performance drops sharply.
Not all carbohydrates are equal. Complex, fibre-rich sources (oats, whole grains, legumes, vegetables) digest slowly, providing sustained energy and supporting gut health. Simple carbohydrates (white bread, sugar, fruit juice) digest rapidly — useful around workouts, problematic in excess throughout the day.
Best sources: oats, brown rice, sweet potato, quinoa, whole grain bread, fruit, vegetables.
Fats
Dietary fat provides 9 kcal per gram — more than double the other macronutrients. Despite its caloric density, fat is essential for hormone production (including testosterone and oestrogen), fat-soluble vitamin absorption (A, D, E, K), cell membrane integrity, and brain function.
A minimum of 0.5–1.0g per kg bodyweight per day is recommended for hormonal health. Dropping fat too low — as some low-fat diets advocate — can suppress sex hormone production, impair recovery, and negatively affect mood. Prioritise unsaturated fats (olive oil, avocado, nuts, oily fish) over saturated and avoid trans fats.
Best sources: olive oil, avocado, salmon, mackerel, nuts, seeds, eggs.
Flexible Dieting and IIFYM: What the Research Says
"If It Fits Your Macros" (IIFYM) is a nutritional approach in which any food is acceptable as long as it fits within your daily macronutrient and calorie targets. It arose as a counter-movement to rigid "clean eating" protocols that demonised entire food categories.
The scientific basis is sound: body weight and composition are determined by the total calories and macronutrient balance consumed over time, not by the specific food sources those macros come from. A gram of protein from chicken and a gram of protein from a protein shake have identical effects on muscle protein synthesis.
The practical advantage of flexible dieting is adherence. Studies on dietary adherence consistently show that the best diet for an individual is the one they can actually stick to long-term. Rigid elimination diets produce faster short-term results but higher dropout rates.
The caveat: micronutrients and fibre matter for health even if they do not directly influence body composition. A macro-perfect diet of processed food will leave micronutrient gaps that whole foods would fill. Aim for 80% of your calories from minimally processed, nutrient-dense sources and allow 20% flexibility — this is sometimes called the "80/20 rule."
Macro Targets by Goal
Percentages refer to proportion of total daily calories. Our calculator generates the gram targets automatically based on your TDEE.
How to Track Your Macros in Practice
Step 1: Get a Food Scale
Accurate macro tracking requires weighing food in grams, not using volume measurements like cups or tablespoons. A basic digital food scale costs under £10 and is the single most impactful tool for nutritional accuracy. Research shows people underestimate portion sizes by 20–50% without one.
Step 2: Use a Tracking App
Apps like MyFitnessPal, Cronometer, and Lose It! have extensive food databases with barcode scanners. Log everything — including oils used in cooking, drinks, and condiments. These seemingly minor additions often account for 200–400 hidden calories per day.
Step 3: Meal Prep to Reduce Friction
Tracking is much easier when you eat the same meals repeatedly. Prepare protein sources (chicken breast, mince, fish) in bulk, cook a large batch of grains (rice, oats, potatoes), and keep healthy fat sources (nuts, avocado, olive oil) accessible. Repeating meals reduces decision fatigue and tracking time to minutes per day.
Step 4: Pre-log Your Day
Log all your meals the night before or first thing in the morning. This lets you adjust before you eat — moving a meal earlier or later, swapping an ingredient — rather than scrambling to fix overages at the end of the day. Pre-logging also reduces impulsive eating by making your plan concrete and visible.
Step 5: Track Trends, Not Days
Missing your macros on one day matters far less than your weekly average. If you eat 300 kcal over target on Saturday, one extra 30-minute walk covers it over the following three days. Weekly average intake is the number that drives body composition change — daily perfection is neither required nor realistic for most people.
Step 6: Adjust Every 2–4 Weeks
As your weight changes, so do your calorie needs. Recalculate your targets every 2–4 weeks or whenever your weight has shifted by more than 2–3 kg. As you lose weight, maintenance calories drop, so your deficit needs to be recalculated to keep producing results. This is the most commonly overlooked step in long-term dieting.
Nutrient Timing: Does It Matter?
Nutrient timing — eating specific macronutrients at specific times relative to training — was heavily emphasised in fitness culture during the 2000s. The "anabolic window" concept suggested you had 30–60 minutes post-workout to consume protein or risk losing muscle. More recent research has moderated this view significantly.
Pre-Workout
A mixed meal containing carbohydrates and protein 1–3 hours before training ensures glycogen availability and blood amino acids are elevated during the session. If training fasted, a protein shake within 30 minutes beforehand can reduce muscle catabolism.
Post-Workout
Muscle protein synthesis is elevated for 24–48 hours post-training, not just the first hour. Total daily protein intake matters far more than exact post-workout timing. That said, consuming 25–40g of protein within a few hours of training is still good practice — just not as urgent as once believed.
Before Bed
Consuming slow-digesting protein (casein from cottage cheese, Greek yogurt, or a casein shake) before bed extends the overnight period of positive protein balance. Research by Dr. Luc van Loon shows this improves muscle protein synthesis rates and long-term lean mass gains compared to a no-protein condition.
Related Reading
Macro Questions
Macros (macronutrients) are the three nutrients that supply calories: protein (4 kcal/g), carbohydrates (4 kcal/g), and fats (9 kcal/g). Tracking them lets you shape body composition, not just weight.
A common target is 40% protein, 30% carbohydrates, 30% fat in a calorie deficit. The high protein protects lean muscle while you cut. Use our calculator to get an exact gram target for your stats.
For active adults, research supports 1.6-2.2 g of protein per kg of bodyweight to maximise muscle protein synthesis. Sedentary adults need around 0.8 g/kg as a minimum.
Around 30% protein, 45% carbohydrates, 25% fat in a 250-500 kcal surplus tends to maximise lean mass while limiting fat gain. Carbs fuel hard training; protein supports repair.
Calories drive weight change; macros drive composition. If you only care about scale weight, counting calories is enough. If you want to gain muscle, lose fat, or both, tracking macros gives a much better outcome.
No. Aim for plus or minus 5 g protein, 10 g carbs and 5 g fat of your target. Weekly averages matter far more than any single day.