Macro Calculator
Calculate your daily protein, carb, and fat targets based on your health goals.
Calculate your daily calorie needs and macronutrient targets based on your body stats, activity level, and weight goal.
How Macro Targets Are Calculated
BMR and TDEE — the starting point
Your calorie target begins with BMR (Basal Metabolic Rate) — the calories your body burns at complete rest, calculated using the Mifflin-St Jeor equation. BMR is then multiplied by an activity factor (×1.2 sedentary to ×1.9 extra active) to produce your TDEE — the calories you actually burn through a typical day including all exercise. TDEE is your maintenance level: eat at this figure and your weight stays stable.
Goal-based calorie adjustment
The calculator adjusts your TDEE up or down based on your goal. A 500 kcal/day deficit produces roughly 0.45 kg (1 lb) of fat loss per week (500 × 7 ≈ 3,500 kcal ≈ 0.45 kg). A 250 kcal deficit gives slower, more sustainable loss of ~0.25 kg per week. The calculator enforces a 1,200 kcal minimum to prevent dangerously low intakes. For muscle gain, a 250–500 kcal surplus supports gradual growth with minimal fat accumulation. Track changes in body composition alongside calorie targets with the body fat calculator.
How the macro split works
After setting the calorie target, it is divided across three macronutrients using fixed ratios: protein 30% (÷ 4 kcal/g), carbohydrates 40% (÷ 4 kcal/g), and fat 30% (÷ 9 kcal/g). The 30% protein allocation typically satisfies the needs of moderately active people and is intentionally set above the common 20% recommendation to account for muscle preservation. The goal comparison table shows the full macro breakdown at every calorie level. For a pure daily protein intake target, see the protein calculator.
When to adjust the default split
The 30/40/30 split is a sound starting point, not a fixed rule. Athletes building muscle may benefit from higher protein (35–40%) and lower carbs. Endurance athletes often perform better with more carbohydrates (50–55%) to fuel training. During a fat loss phase, increasing protein to 35–40% helps preserve lean muscle mass. Adjust in 5% increments, keep total calories constant, and track results over 2–3 weeks before changing further.
Worked example
Female, 30 yrs, 65 kg, 165 cm, moderately active, goal: lose fat. Mifflin BMR = 1,387 kcal, TDEE (×1.55) = 2,150 kcal, deficit target = 1,750 kcal/day. Macros at 30/40/30: protein = 1,750 × 0.30 ÷ 4 = 131 g; carbs = 1,750 × 0.40 ÷ 4 = 175 g; fat = 1,750 × 0.30 ÷ 9 = 58 g.
Related calculations
Macros are a share of a daily total, so start with the BMR calculator and read BMR vs TDEE for how activity is added. For protein specifically, the protein calculator works from body weight and training load, and the steps calculator covers the walking side.
What Are Macros? Carbs, Protein and Fat Explained
Protein — the building block
Protein is made of amino acids used to build and repair muscle tissue, produce enzymes and hormones, and support immune function. Each gram provides 4 kcal. Complete proteins (meat, fish, eggs, dairy) contain all nine essential amino acids; plant proteins can be combined to achieve the same effect (e.g. rice and beans). The body cannot store excess amino acids long-term, making regular intake spread across the day important for muscle synthesis.
Carbohydrates — the primary fuel
Carbohydrates are the body's preferred energy source, particularly for the brain and during high-intensity exercise. Each gram provides 4 kcal. They are stored as glycogen in muscles and the liver — glycogen fuels intense training, and depleted stores cause fatigue. Quality matters: complex sources (oats, sweet potato, brown rice) digest slowly and sustain energy levels; refined carbs (white bread, added sugar) cause rapid blood glucose spikes and promote fat storage if eaten in excess.
Fat — essential, not the enemy
Dietary fat provides 9 kcal per gram and is essential for hormone production, fat-soluble vitamin absorption (A, D, E, K), and cell membrane integrity. The body cannot function without adequate fat. Source quality matters: unsaturated fats (olive oil, avocados, nuts, oily fish) are associated with reduced cardiovascular risk; saturated fats should be moderated; trans fats (partially hydrogenated oils) should be avoided. Fat's high calorie density means even modest portions contribute significantly to daily totals.
Tracking your macros
The most practical method is to log food in an app (MyFitnessPal, Cronometer) which converts portions into grams of protein, carbs, and fat. Precision matters most in the first few weeks to calibrate your understanding of portion sizes — after that, most people can maintain targets without logging every meal. A flexible dieting approach (IIFYM — If It Fits Your Macros) focuses on hitting daily totals across any food choices rather than restricting specific foods, which tends to improve long-term adherence.
What tracking macros actually involves
Counting macros means weighing or measuring portions and logging the protein, carbohydrate, and fat content of everything you eat, keeping daily totals within a target range. The practical value is largely educational: most people have significant misconceptions about what everyday portions weigh and what macros common foods contain. After 4–8 weeks of accurate logging, most people can maintain targets with a rough mental estimate rather than weighing everything. Strict daily precision is not necessary indefinitely — the goal is to build a calibrated understanding of food composition.
High-protein vs high-carbohydrate diets
When total calories and protein are equated, high-protein and high-carbohydrate diets produce similar fat loss and muscle preservation outcomes — the research does not consistently favour either. High-protein diets tend to be more satiating between meals and reduce cravings, making a calorie deficit easier to sustain. High-carbohydrate diets better support sustained high-intensity training, because glycogen (stored from carbohydrate) is the primary fuel for efforts above about 70% of maximum effort. Choose the distribution that matches your training demands and that you can realistically maintain.
Macros for muscle gain vs fat loss
The two goals have different priorities. For muscle gain, protein at 1.6–2.2 g/kg combined with a modest calorie surplus (250–500 kcal above TDEE) is the foundation; carbohydrates should be generous to fuel training and spare protein for repair. For fat loss, protein climbs to 1.8–2.4 g/kg to preserve muscle during the deficit; carbohydrates can be lower without significantly affecting performance unless training volume is high. Fat can be set at 20–25% of calories in either phase without adverse effects, provided essential fatty acids are met.
Frequently Asked Questions
How does the macro calculator work out my daily calorie target?
The calculator estimates your BMR using the Mifflin-St Jeor equation, multiplies it by your activity factor to get TDEE, then adjusts up or down by your goal amount. A 500 kcal/day deficit or surplus produces roughly 0.45 kg (1 lb) of weight change per week — the goal comparison table shows all options side by side.
How are macros split between protein, carbs, and fat?
Your calorie target is divided across protein (30%), carbohydrates (40%), and fat (30%) as a balanced starting point. Protein and carbs yield 4 kcal per gram; fat yields 9 kcal per gram. These ratios can be adjusted for different goals — more protein for muscle building, more carbs for endurance performance.
How accurate are the macro calculator's estimates?
BMR formulas have a typical error margin of ±10% — individual needs vary based on genetics, body composition, thyroid function, and other factors. Use the results as a starting point and adjust by 100–200 kcal based on how your weight changes over 2–3 weeks. Consult a registered dietitian before making significant dietary changes, particularly if you have a medical condition.
Should I adjust my macros for my specific goal?
Yes — the default 30/40/30 split works for general fitness and weight maintenance, but it is a starting point. For muscle gain, increasing protein to 35–40% is beneficial. For endurance sports, raising carbohydrates to 50–55% better supports training. For fat loss, a higher protein ratio (35–40%) helps preserve lean muscle during the deficit. Adjust in 5% increments and assess over 2–3 weeks.
Evidence & Methodology
How This Page Is Grounded
Method
Estimates BMR with Mifflin–St Jeor, applies an activity factor, adjusts calories for the selected goal and converts calorie shares to grams.
Important limitation: Energy and macronutrient targets are starting estimates, not personalised medical or dietetic advice.
Primary Sources
- A new predictive equation for resting energy expenditure in healthy individuals PubMed
- Dietary reference values for protein European Food Safety Authority
Quality Checks
Energy totals and the 4/4/9 kcal-per-gram conversion are checked across goal modes.
See how sources are selected and corrections are handled in our Editorial & Calculation Methodology, and which automated checks this page has to pass in How We Test.