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Macro Calculator

Calculate your optimal daily protein, carbohydrate, and fat intake based on your goals and activity level.

Macronutrient Calculations

Protein (grams)

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Carbs & Fat (grams)

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yrs
lb
ft
in

What are Macronutrients?

Macronutrients, or 'macros,' are the three main nutrients that provide energy (calories) to your body: protein, carbohydrates, and fat. Unlike micronutrients (vitamins and minerals), you need macros in large amounts - measured in grams rather than milligrams.

Each macronutrient plays unique roles in your body and provides different amounts of energy: protein and carbohydrates provide 4 calories per gram, while fat provides 9 calories per gram. Balancing these nutrients optimizes health, performance, and body composition.

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Protein

Builds and repairs muscle, supports immune function, and creates enzymes and hormones. 4 cal/gram.

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Carbohydrates

Your body's preferred energy source, fuels brain function and intense exercise. 4 cal/gram.

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Fat

Essential for hormone production, nutrient absorption, and cell membrane health. 9 cal/gram.

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Energy Balance

Total calories determine weight change; macro ratios affect body composition and performance.

Understanding Macro Ratios

Macro ratios describe the percentage of your daily calories coming from each macronutrient. Different ratios support different goals and lifestyles:

Diet TypeProteinCarbsFatBest For
Balanced 30% 40% 30% General health, sustainable long-term eating
Low Carb 40% 20% 40% Fat loss, blood sugar control, reduced cravings
High Protein 40% 35% 25% Muscle building, athletic performance, satiety
Keto 25% 5% 70% Ketosis, epilepsy management, some find effective for fat loss

Protein: The Building Block

Protein is crucial for anyone looking to improve body composition. It has the highest thermic effect (your body burns more calories digesting it), promotes satiety, and is essential for muscle maintenance and growth.

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Muscle Protein Synthesis

Consuming adequate protein (0.7-1g per lb of body weight) maximizes muscle building when combined with resistance training. Spread intake across 3-5 meals for optimal synthesis.

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Thermic Effect

Protein has a thermic effect of 20-30%, meaning you burn 20-30% of protein calories just digesting it. Carbs are 5-10%, fat is 0-3%.

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Satiety Factor

Protein is the most filling macronutrient. Higher protein diets reduce hunger, making calorie restriction more sustainable for weight loss.

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Quality Sources

Complete proteins (meat, fish, eggs, dairy) contain all essential amino acids. Plant-based eaters should combine sources (rice + beans) for complete profiles.

Carbohydrates: The Energy Source

Carbohydrates are your body's preferred fuel source, especially for high-intensity exercise and brain function. While not technically 'essential,' they significantly impact energy, performance, and mood.

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Exercise Performance

Carbs fuel glycolytic activities (weight training, sprinting, HIIT). Low carb intake impairs high-intensity performance. Endurance athletes need 3-5g/lb on heavy training days.

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Brain Function

Your brain uses about 120g of glucose daily. While it can adapt to ketones, many people report better focus and mood with moderate carb intake.

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Insulin Response

Choose complex carbs (oats, brown rice, vegetables) over simple sugars for stable blood sugar. Fiber content slows digestion and improves satiety.

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Timing Matters

Consuming carbs around workouts enhances performance and recovery. Post-workout carbs replenish glycogen and support muscle protein synthesis.

Fat: The Essential Nutrient

Dietary fat is essential for life - your body cannot produce all the fatty acids it needs. Fat supports hormone production, vitamin absorption, and provides sustained energy for low-intensity activities.

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Hormone Production

Cholesterol from dietary fat is the precursor for testosterone, estrogen, and cortisol. Very low fat diets can impair hormone levels and mood.

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Vitamin Absorption

Fat-soluble vitamins (A, D, E, K) require dietary fat for absorption. Eating vegetables with healthy fats increases nutrient uptake significantly.

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Types of Fat

Prioritize unsaturated fats (olive oil, nuts, avocados, fish). Limit saturated fat to <10% of calories. Avoid trans fats completely.

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Calorie Density

At 9 cal/gram, fat is calorie-dense. This makes it satisfying but requires careful tracking. A tablespoon of oil adds 120 calories.

How to Track Your Macros

Successful macro tracking requires consistent measurement and logging. Here's how to get started:

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Use a Food Tracking App

Apps like MyFitnessPal, Cronometer, or MacroFactor have extensive databases. Scan barcodes or search foods to log meals quickly and accurately.

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Invest in a Food Scale

Eyeballing portions is notoriously inaccurate. A $15 food scale pays dividends in accuracy. Weigh proteins raw, grains dry, and everything else as you eat it.

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Plan Meals Ahead

Pre-logging meals helps you hit targets. Build 'go-to' meals that fit your macros perfectly, then rotate them for variety while staying consistent.

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Allow Flexibility

Aim for within ±5g of protein target (most important), ±10g for carbs and fat. Perfect adherence isn't necessary - consistency over time matters more.

Adjusting Macros for Results

Your initial macro targets are starting points. Adjust based on progress and how you feel:

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Not Losing Weight?

If scale isn't moving after 2-3 weeks, reduce total calories by 10% (cut carbs and/or fat). Keep protein high to preserve muscle during the deficit.

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Not Gaining?

Add 200-300 calories primarily from carbs. Ensure protein stays at 0.7-1g/lb. Extra carbs fuel training and support muscle growth.

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Feeling Fatigued?

Low energy often signals insufficient carbs or total calories. Add 25-50g carbs around workouts first, then assess.

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Strength Dropping?

In a deficit, strength loss often means cutting too aggressively or protein too low. Slow the rate of loss and ensure adequate protein.

How to use this macro calculator

  1. Pick a unit system using the Imperial / Metric toggle above the form. Imperial expects pounds and feet/inches; Metric expects kilograms and centimeters.
  2. Enter your Age in years and tap Male or Female for Gender. The Mifflin-St Jeor formula uses these to estimate your resting metabolic rate.
  3. Type your Weight in the matching unit, then your Height (feet plus inches for Imperial, or a single centimeters value for Metric).
  4. Pick an Activity Level — Sedentary (1.2), Light (1.375), Moderate (1.55), Active (1.725), or Very Active (1.9). Choose the option that matches a typical week, not your best week.
  5. Choose a Goal — Lose Weight (-500 cal/day), Maintain Weight, or Build Muscle (+300 cal/day). The calculator applies this adjustment to your maintenance calories.
  6. Pick a Diet Type — Balanced (30/40/30), Low Carb (40/20/40), High Protein (40/35/25), or Keto (25/5/70). This sets the protein/carb/fat split.
  7. Click Calculate Macros. The result panel shows your daily calorie target plus grams of protein, carbohydrate, and fat to hit it.

Examples

Maintenance on a balanced diet

A 30-year-old man, 175 lb, 5'10", exercises 3–5 days per week and wants to maintain his current weight while eating a conventional mixed diet.

ResultAbout 2,728 daily calories at a 30/40/30 split: 205g protein, 273g carbs, 91g fat.

Mifflin-St Jeor gives BMR = 10×79.4 + 6.25×177.8 − 5×30 + 5 ≈ 1,760 kcal. Multiplying by the Moderate activity factor 1.55 lands at ~2,728 kcal, and no goal adjustment is applied because he picked Maintain. The Balanced preset splits those calories 30% protein / 40% carbs / 30% fat, then divides protein and carb calories by 4 and fat calories by 9 to get grams.

Fat loss on a high-protein cut

A 28-year-old woman, 145 lb, 5'5", trains 1–3 days a week and wants to lose body fat while preserving muscle.

ResultAbout 1,409 daily calories at a 40/35/25 split: 141g protein, 123g carbs, 39g fat.

BMR for a 65.8 kg, 165.1 cm, 28-year-old female is roughly 1,389 kcal. Scaling by Light activity (1.375) gives a maintenance TDEE near 1,909 kcal, and the Lose goal removes 500 to land at ~1,409 kcal. Protein lands near 141g — about 1.0 g per pound — which is consistent with ACSM and ISSN recommendations for protecting lean mass in a deficit.

Muscle gain on a ketogenic diet

A 25-year-old man, 170 lb, 6'0", trains 6–7 days a week, wants to add muscle, and is experimenting with very low carbohydrate eating.

ResultAbout 3,395 daily calories at a 25/5/70 split: 212g protein, 42g carbs, 264g fat.

BMR is 10×77.1 + 6.25×182.9 − 5×25 + 5 ≈ 1,794 kcal, the Active multiplier 1.725 brings TDEE to ~3,095 kcal, and the Build Muscle adjustment adds 300 for a 3,395 kcal target. The Keto split forces only 5% of calories from carbs — about 42g — which is the upper end of most clinical ketosis protocols. The 264g fat target is unusually high; expect to plan around fatty cuts, oils, nuts, and dairy.

How it works

The calculator first estimates your basal metabolic rate (BMR) with the Mifflin-St Jeor equation, the most accurate predictive formula for healthy adults according to the Academy of Nutrition and Dietetics. For men: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5. For women: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161. Imperial inputs are converted to kg and cm before the formula runs.

Your BMR is then multiplied by an activity factor — 1.2 for sedentary up to 1.9 for very active — to estimate total daily energy expenditure (TDEE), the calories you burn on a typical day including movement and exercise. If you picked Lose Weight, 500 kcal is subtracted (yielding roughly 1 lb per week of loss). If you picked Build Muscle, 300 kcal is added (a moderate surplus that supports lean gain without large fat gain).

Finally, the target calorie total is split by your chosen diet preset. Protein and carbohydrate calories are divided by 4 to yield grams; fat calories are divided by 9. The four presets — Balanced (30/40/30), Low Carb (40/20/40), High Protein (40/35/25), and Keto (25/5/70) — all sit inside or near the USDA Acceptable Macronutrient Distribution Ranges (AMDR) of 10–35% protein, 45–65% carbs, and 20–35% fat, except Keto which intentionally falls outside the carb range.

These outputs are population-level estimates, not measurements. Real-world energy needs vary by 10–20% across individuals of the same size and activity because of differences in non-exercise activity, gut microbiome, sleep, and lean mass. Track your weight for two to three weeks at the calculated target before deciding whether to adjust.

When to use this calculator

  • Setting a starting point for a diet. Use it on day one of a fat-loss, recomp, or lean-bulk program to get protein, carb, and fat grams that match your size and goal — instead of guessing or copying someone else's macros.
  • Picking between diet styles. Compare the four presets to see how a low-carb, high-protein, or ketogenic split changes your grams. This makes the trade-offs concrete before you commit to a way of eating.
  • Resetting after a weight change. Recalculate after every 10 lb of loss or gain. Your BMR drops as you lose weight and rises as you add lean mass, so old targets stop matching real expenditure.
  • Planning meals for a training week. Use the gram totals as daily targets in apps like MyFitnessPal or Cronometer. Knowing your numbers makes it possible to spread protein across meals and time carbs around training.
  • Coaching a client or family member. A starting macro template tied to age, sex, height, weight, activity, and goal is a useful prescription tool. Pair it with weekly weigh-ins and a simple progress photo schedule.

Common mistakes

  • MistakePicking an activity level that reflects your best week, not your typical one.
    FixIf you train hard three days but sit at a desk the other four, you are Moderate (1.55), not Active (1.725). Over-estimating activity is the single most common reason calculated calories run too high.
  • MistakeTreating the calculated calories as exact.
    FixMifflin-St Jeor has a standard error of roughly ±10% even for healthy adults. Run the target for two to three weeks, weigh in 3–5 times per week, and adjust by 100–200 kcal if the trend does not match your goal.
  • MistakeChasing exact macro hits to the gram every day.
    FixAim within ±5g of protein and ±10g of carbs and fat. The ISSN protein position stand and the AMDR ranges describe weekly averages, not single days. Consistency beats perfection.
  • MistakeCutting fat below ~20% of calories for long stretches.
    FixVery low fat intake can impair sex hormones, vitamin A/D/E/K absorption, and satiety. Keep fat near the bottom of the AMDR (20%) at minimum, even on aggressive cuts.
  • MistakeUsing these numbers during pregnancy, illness, or for children.
    FixPredictive equations are validated for healthy non-pregnant adults. Pregnant or breastfeeding women, people in active disease states, and anyone under 18 should work with a registered dietitian for individualized macros.
  • MistakeWeighing food cooked instead of raw for protein and grains.
    FixNutrition labels reference raw weight. 100g raw chicken breast becomes ~75g cooked but still has the same protein content. Weigh proteins raw and grains dry whenever possible.

Frequently asked questions

How much protein do I need?

The RDA is 0.36 g per pound of body weight (0.8 g/kg), but that minimum is set to prevent deficiency, not to optimize body composition. The ACSM and the International Society of Sports Nutrition recommend 0.6–0.9 g per pound (1.4–2.0 g/kg) for active adults and 0.7–1.0 g/lb during aggressive fat loss to preserve muscle. The presets in this calculator land inside that range for most users.

Is a high-fat diet healthy?

Total fat intake within the AMDR (20–35% of calories) is consistent with cardiovascular health when most of it comes from unsaturated sources like olive oil, nuts, avocados, and fatty fish. The USDA Dietary Guidelines also flag saturated fat — keep it under 10% of total calories and avoid industrial trans fats entirely. Higher-fat patterns like keto can be safe for many people but have not been studied for decades the way moderate-fat patterns have.

What is the AMDR?

The Acceptable Macronutrient Distribution Range is set by the National Academies' Food and Nutrition Board and is the percentage of total calories each macronutrient should provide to reduce chronic disease risk: 10–35% protein, 45–65% carbohydrate, and 20–35% fat. The Balanced, Low Carb, and High Protein presets all sit at or inside these bounds; Keto sits outside the carb range by design.

Do I need to count macros if I'm not athletic?

No. For weight maintenance or modest weight changes, simpler tools — hand portions, plate models, or food group targets like the USDA MyPlate — work fine. Macro counting becomes useful when you have a specific body-composition goal, a sport with strict weight categories, or a medical reason (insulin resistance, ketogenic therapy for epilepsy) to control specific macros.

Why does protein matter so much for fat loss?

Three reasons. First, protein has the highest thermic effect of food (20–30% of its calories are burned during digestion), so net energy intake is lower. Second, protein is the most satiating macronutrient, which makes a calorie deficit easier to adhere to. Third, in a deficit your body breaks down both fat and lean tissue for fuel; adequate protein combined with resistance training shifts that loss strongly toward fat.

How accurate are these targets?

Mifflin-St Jeor predicts measured resting energy expenditure within about ±10% for most healthy adults. Activity multipliers add another layer of estimation. Expect your real maintenance calories to fall within ±10–15% of the calculated target. Treat the output as a hypothesis to test for 2–3 weeks, then adjust based on weight trend, not as a precise prescription.

Should I track macros or just calories?

Calories alone determine weight direction; macros determine body composition. If your only goal is to weigh less, counting calories is enough. If you care about how much of that change is fat versus muscle — or about training performance, blood sugar, or satiety — tracking the macro split is worth the extra effort, especially the protein number.

How accurate do I need to be with macros?

Aim for ±5g on protein (most important for muscle and satiety), ±10g on carbs and fat. Hitting exact numbers daily isn't necessary — focus on weekly averages. Consistency matters more than perfection.

What if I go over on one macro?

Going over on protein is rarely a problem. If you exceed carbs or fat, you can reduce the other slightly to stay near your calorie target, or just accept a slightly higher day and return to normal tomorrow. One day won't ruin progress.

Should I eat the same macros on rest days?

Most people do fine keeping macros consistent. Some prefer cycling carbs — higher on training days, lower on rest days — while keeping weekly totals similar. For most recreational exercisers, consistency is simpler and equally effective.

Are all calories equal?

For pure weight change, yes — a calorie deficit causes loss regardless of source. But for body composition, health, and satiety, macro sources matter. Protein builds muscle, fiber promotes health, and nutrient-dense foods outperform empty calories.

How often should I recalculate my macros?

Recalculate when weight changes by 10+ pounds, your activity level significantly changes, or you're plateauing for 3+ weeks. As you get lighter, your calorie needs decrease and macros should adjust accordingly.

Sources

Methodology

This calculator estimates BMR with the Mifflin-St Jeor equation (Mifflin et al., 1990): for men, BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5; for women, BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161. Imperial inputs are converted to kg and cm first. BMR is multiplied by an activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 active, 1.9 very active) to estimate TDEE, then −500 kcal is applied for Lose Weight or +300 kcal for Build Muscle. Target calories are split into protein, carbohydrate, and fat using one of four diet presets — Balanced (30/40/30), Low Carb (40/20/40), High Protein (40/35/25), or Keto (25/5/70) — and divided by 4 kcal/g (protein, carbs) or 9 kcal/g (fat) to produce grams. Three of the four presets sit inside the USDA AMDR (10–35% protein, 45–65% carbs, 20–35% fat); Keto intentionally falls below the carb range. Outputs are population estimates and are not appropriate during pregnancy, illness, or for children.

Learn more about our methodology →

Pro Tips

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  • Try different scenarios to compare outcomes
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