Macro Calculator
Get personalised daily targets for protein, carbs, and fat based on your body stats, activity level, and goal — free, no account required, nothing leaves your device.
Fill in your details above to see your personalised macro targets.
How It Works
Enter your details
Select sex, unit system, then enter age, weight, and height. The calculator uses the Mifflin–St Jeor equation to estimate your Basal Metabolic Rate (BMR).
Pick your activity level
Choose from five levels — sedentary to extremely active. Your BMR is multiplied by an activity factor to give your Total Daily Energy Expenditure (TDEE).
Choose your goal
Select from Weight Loss, Cutting, Maintenance, Muscle Gain, or Keto. Each goal adjusts your calorie target and applies an evidence-informed macro split.
Read your macro targets
See your daily target calories plus individual protein, carbohydrate, and fat targets in grams and kcal — with a visual distribution bar.
What Is a Macro Calculator?
A macro calculator estimates how many grams of protein, carbohydrates, and fat you should eat each day to reach a specific body composition goal. Rather than just counting total calories, tracking macros gives you more granular control over your physique — particularly important for preserving muscle during weight loss, fuelling athletic performance, or gaining lean mass.
The Three Macronutrients
- Protein (4 kcal/g) — the building block of muscle, enzymes, and hormones. Protein is highly satiating and has the highest thermic effect of all macros (20–30% of its calories are burned during digestion). It is especially important when eating in a calorie deficit.
- Carbohydrates (4 kcal/g) — the body's preferred fuel source, particularly for high-intensity exercise. Carbs also spare muscle protein from being used for energy. Cutting carbs too low can impair performance and mood.
- Fat (9 kcal/g) — essential for hormone production (including testosterone and oestrogen), fat-soluble vitamin absorption (A, D, E, K), and brain function. Fat is calorie-dense, so small changes in fat intake have a larger effect on overall calories.
How This Calculator Works
This tool uses the Mifflin–St Jeor equation to calculate your Basal Metabolic Rate (BMR), then multiplies it by an activity factor to get your TDEE:
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Your target calories are then set by adjusting your TDEE based on your goal, and distributed across macros using a percentage split tailored to that goal:
| Goal | Calorie Adjustment | Protein | Carbs | Fat |
|---|---|---|---|---|
| Weight Loss | −500 kcal | 35% | 35% | 30% |
| Cutting | −250 kcal | 40% | 30% | 30% |
| Maintenance | ± 0 kcal | 25% | 50% | 25% |
| Muscle Gain | +300 kcal | 30% | 45% | 25% |
| Keto | −300 kcal | 25% | 5% | 70% |
Understanding Your Macro Targets
Once you have your gram targets, the easiest way to hit them is to track your food using a nutrition app or food label reader. Here are rough mental benchmarks:
- Protein sources: chicken breast (~31 g protein per 100 g), Greek yoghurt (~10 g/100 g), eggs (~6 g each), whey protein (~22–25 g per scoop).
- Carbohydrate sources: oats (~60 g carbs/100 g dry), rice (~28 g/100 g cooked), sweet potato (~20 g/100 g cooked), banana (~23 g each).
- Fat sources: avocado (~15 g fat per half), olive oil (~14 g/tbsp), almonds (~49 g fat/100 g), salmon (~13 g fat/100 g).
Macro Calculator vs. Calorie Counter
A calorie counter tells you how much total energy to consume — useful for weight management but insufficient for body composition goals. A macro calculator goes one step further by specifying where those calories come from. Two people eating 2,000 kcal/day can have vastly different results depending on their macro split: the high-protein, lower-carb approach typically yields more muscle retention and greater satiety during a cut.
Features
- Five goal presets: weight loss, cutting, maintenance, muscle gain, and keto — each with calibrated macro splits.
- Mifflin–St Jeor TDEE: the most validated equation for general-population BMR estimation.
- Visual macro bar: instantly shows your protein/carb/fat ratio at a glance.
- Metric and imperial support: switch between kg/cm and lbs/ft seamlessly.
- Instant results: all values update in real time as you type — no submit button.
- Your data stays private: all calculations run locally in your browser — nothing is uploaded or stored.
- No account required: open the page and start in seconds.
Frequently Asked Questions
What are macros?
Macros — short for macronutrients — are the three main categories of nutrients that provide calories: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). Tracking macros gives you more control over body composition than counting calories alone.
How does this macro calculator work?
The calculator estimates your TDEE using the Mifflin–St Jeor equation and your activity level, adjusts your calorie target based on your chosen goal, then distributes those calories across protein, carbs, and fat using evidence-informed percentage splits.
How much protein do I need per day?
Protein needs vary by goal. This calculator uses 35–40% of calories from protein for weight loss and cutting goals, 25–30% for maintenance and muscle gain, and 25% for keto. In absolute terms this typically falls in the 1.6–2.2 g/kg body weight range recommended by sports nutrition research.
What is the difference between weight loss and cutting?
Weight loss uses a 500 kcal/day deficit (≈ 0.5 kg/week loss) with a 35% protein split. Cutting uses a smaller 250 kcal/day deficit with a higher 40% protein split — designed for athletes who want to lose fat while protecting as much muscle as possible.
How many carbs per day on keto?
The keto preset targets 5% of calories from carbs. On a 1,800 kcal target this is roughly 22 g of net carbs per day — within the typical 20–50 g/day range needed to maintain nutritional ketosis for most people.
How accurate are the macro targets?
The TDEE estimate is accurate to within ±10% for most adults. Macro percentage splits are evidence-informed starting points. Individual factors — genetics, hormones, sleep, and stress — all affect how your body uses macros. Use the results as a baseline and adjust over 3–4 weeks based on real-world progress.
Is this medical advice?
No. This calculator provides estimates for informational purposes only and is not a substitute for advice from a registered dietitian, nutritionist, or physician. Consult a qualified healthcare professional before making significant dietary changes, especially if you have a medical condition.
Is my data stored or sent anywhere?
No. All calculations happen entirely in your browser using JavaScript. Nothing you enter — age, weight, height, sex, or goal — is ever sent to or stored on any server.
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