Mifflin-St Jeor · 4 Goals · Updated 2026

Macro Calculator

Calculate your daily protein, carbohydrates, and fat targets based on your body, activity level, and goal. Cut fat, maintain, lean bulk, or build mass: all with tailored macro splits.

Last updated · Protein guidance checked against the 2025 to 2030 Dietary Guidelines for Americans and National Academies DRIs

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Macro Calculator
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Enter your details and goal to get your personalized macro targets.

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How Macro Splits Work by Goal

A moderately active 28-year-old man who is 5'10" and 175 lb needs about 2,744 calories a day to maintain his weight, split as 175 g protein, 292 g carbs and 97 g fat. The calculator finds your calories with Mifflin-St Jeor, adjusts them for your goal, and divides them into protein, carbs and fat, with protein capped at 2.2 g per kg of body weight.

Macros (macronutrients) are the three calorie-providing nutrients: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). The ratio of these nutrients matters alongside total calories: the same calorie intake with different macro splits produces different body composition results. Higher protein preserves muscle during a deficit. More carbohydrates fuel performance and recovery. Adequate fat supports hormonal health.

GoalCalorie AdjustProteinCarbsFat
Cut (Lose Fat)−500/day40%35%25%
MaintainTDEE30%40%30%
Lean Bulk+250/day30%45%25%
Bulk (Gain Mass)+500/day25%50%25%

Why Protein Is Higher on a Cut

During a calorie deficit, muscle protein breakdown increases. Setting protein at 1.6 to 2.2 g per kg of body weight (about 0.7 to 1 g per pound) is the best supported strategy for preserving lean mass while losing fat. High protein also increases satiety through the thermic effect of food (20-30% of protein calories are burned during digestion) and reduces hunger hormones.

Carbs and Performance

Carbohydrates are the primary fuel for high-intensity exercise, stored as glycogen in muscles and liver. Higher carb ratios (45-55%) benefit athletes and those doing strength or HIIT training. Lower carb intakes (20-35%) may suit sedentary individuals or those following low-carb/ketogenic approaches. Carb timing around workouts (30-60g within 1 hour post-workout) maximizes glycogen replenishment.

Dietary Fat Minimum

Fat should never fall below 20% of total calories. Essential fatty acids (omega-3 and omega-6) cannot be synthesized by the body. Fat is necessary for absorption of fat-soluble vitamins (A, D, E, K), testosterone and estrogen production, cell membrane integrity, and brain function. Reducing fat below 20% of calories can impair hormonal function, particularly testosterone in men.

Flexible Dieting vs Strict Macros

Research supports flexible dieting (IIFYM: If It Fits Your Macros) as equally effective as strict meal plans for body composition when total protein and calories are matched. Meeting protein and calorie targets is more important than the specific foods used. However, food quality still matters for micronutrients, fiber, satiety, and long-term health beyond the macro numbers.

Protein Targets in Grams

Grams of protein a day at three common reference levels. The RDA of 0.8 g/kg is the minimum to meet basic needs. The 2025 to 2030 Dietary Guidelines for Americans, released in January 2026, set a goal of 1.2 to 1.6 g/kg. The 1.6 to 2.2 g/kg range comes from research on people who lift weights, especially while losing fat.

Body weightRDA 0.8 g/kgDGA 1.2 to 1.6 g/kgTraining 1.6 to 2.2 g/kg
120 lb (54 kg)44 g65 to 87 g87 to 120 g
140 lb (64 kg)51 g76 to 102 g102 to 140 g
160 lb (73 kg)58 g87 to 116 g116 to 160 g
180 lb (82 kg)65 g98 to 131 g131 to 180 g
200 lb (91 kg)73 g109 to 145 g145 to 200 g
220 lb (100 kg)80 g120 to 160 g160 to 220 g
240 lb (109 kg)87 g131 to 174 g174 to 239 g

If you carry a lot of body fat, base protein on your goal weight or lean mass instead; the lean body mass calculator helps.

Worked Example: Macros for Each Goal

Default profile: man, 28, 5'10" (177.8 cm), 175 lb (79.4 kg), moderately active. BMR = 1,770 and TDEE = 1,770 × 1.55 = 2,744 calories.

GoalCaloriesProteinCarbsFat
Cut (−500)2,244175 g225 g71 g
Maintain2,744175 g292 g97 g
Lean bulk (+250)2,994175 g369 g91 g
Bulk (+500)3,244175 g424 g94 g

Protein stays at 175 g (2.2 g/kg) for every goal because the percentage split would give more than that; the extra calories go to carbs and fat. At maintenance that works out to 26% protein, 43% carbs and 32% fat (rounded). Over three meals: about 58 g protein, 97 g carbs and 32 g fat each.

A smaller person usually gets the full percentage split. A 35-year-old woman, 5'4" and 140 lb, lightly active, has a TDEE of 1,808; her cut is 1,308 calories with 131 g protein, 114 g carbs and 36 g fat.

How the Splits Compare to Federal Ranges

The National Academies set Acceptable Macronutrient Distribution Ranges (AMDR) for adults. They describe intakes linked to lower chronic disease risk with enough essential nutrients.

MacroCalories per gramAMDR, adultsCalculator splits
Protein410% to 35%25% to 40%
Carbohydrate445% to 65%35% to 50%
Fat920% to 35%25% to 30%

The cut split (40% protein, 35% carbs) sits outside the AMDR on purpose, to protect muscle for a few months of dieting. For long-term eating, a split inside the AMDR is the safer default. Whatever the split, aim for about 14 g of fiber per 1,000 calories, the National Academies adequate intake.

These targets are estimates. If you have kidney disease, diabetes or another condition, or are pregnant, check protein and carb targets with your doctor or a registered dietitian. For total calories only, see the calorie calculator.

Method and sources. Calories: Mifflin-St Jeor BMR (10 × kg + 6.25 × cm − 5 × age, +5 men, −161 women) × activity factor, plus the goal adjustment. Grams = calories × share ÷ 4 for protein and carbs, ÷ 9 for fat; protein capped at 2.2 g/kg. All figures were computed with the calculator's own code. Sources: National Academies Dietary Reference Intakes (protein RDA, AMDR, fiber AI); Dietary Guidelines for Americans 2025 to 2030 (USDA and HHS, January 2026). Estimates only, not medical advice.
Macro targets are estimates based on population averages. Individual needs vary. Consult a registered dietitian for personalized nutrition planning, especially for medical conditions or competitive athletics.
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Macro Questions

Macros (macronutrients) are the three main nutrients that provide energy: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). Tracking macros goes beyond just counting calories: you can eat 2,000 calories of different food combinations and get dramatically different results depending on how those calories are divided between protein, carbs, and fat. Protein determines how much muscle you retain or build. Carbohydrates fuel training performance and glycogen storage. Fat supports hormonal function and fat-soluble vitamin absorption. For serious body composition goals, tracking macros produces better results than tracking calories alone.

For muscle building or fat loss while preserving lean mass: 1.6-2.2g per kg of body weight per day (0.7-1g per pound). Sedentary adults need only 0.8g/kg (0.36g/lb) for basic health. The higher end (2.2g/kg) is recommended during aggressive calorie deficits to prevent muscle catabolism, during very high training volumes, and for older adults (due to anabolic resistance). Protein has the highest thermic effect of food (20-30% of protein calories are burned during digestion) and the highest satiety rating, making it the most important macro to prioritize for body composition goals.

For fat loss, a high-protein split works best: approximately 35-40% protein, 30-40% carbohydrates, 20-25% fat. The high protein percentage is critical for preserving lean muscle mass during a calorie deficit. The remaining calories are distributed between carbs and fat based on preference and training demands. There is no single "best" carb-to-fat ratio for fat loss: both low-fat (higher carb) and low-carb (higher fat) approaches produce similar fat loss results when protein is matched and calories are equal. Choose the ratio you can adhere to consistently.

For muscle building (lean bulk): approximately 25-30% protein, 45-50% carbohydrates, 25% fat, with a calorie surplus of 200-300 calories above TDEE. Carbohydrates are prioritized higher than during a cut because they fuel training performance (higher-intensity workouts stimulate more muscle growth) and promote muscle glycogen storage, which is anabolic. Protein needs are slightly lower per unit of total calories (but still high in grams) because the calorie surplus reduces the risk of muscle catabolism. Protein target: 1.6-2.0g per kg of body weight, even during a bulk.

In the United States, fiber is counted as part of total carbohydrates on nutrition labels. In practice, soluble fiber contributes approximately 2 calories per gram (not 4), and insoluble fiber contributes essentially 0 calories. Many macro-tracking apps let you count "net carbs" (total carbs minus fiber), which removes the non-caloric fiber from your carb target. For most macro tracking purposes, tracking total carbs from food labels is simpler and sufficient. If you eat high-fiber foods (30+ grams of fiber daily), tracking net carbs becomes more relevant for accuracy.

Total calories determine body weight change. Macros (especially protein) determine body composition: the ratio of muscle to fat. You can lose weight eating at a calorie deficit with any macro ratio, but high protein significantly improves the ratio of fat to muscle lost. Conversely, you can gain muscle in a surplus regardless of exact macro ratios, but adequate protein and sufficient carbohydrates for training performance maximize muscle gain while minimizing fat. For most people: total calories is the most important variable, protein is the second most important, and the carb-to-fat ratio is the least important of the three.

IIFYM is a flexible dieting approach where you meet your macro targets using any foods you choose, rather than following a strict meal plan. Research supports flexible dieting as equally effective for body composition as rigid meal plans when protein and calorie targets are matched. The appeal is psychological flexibility: no foods are "forbidden" as long as they fit within the day's macro budget. Practical implementation: track protein and total calories most carefully; carbs and fat are more flexible. Critics note that IIFYM can lead to lower micronutrient intake if the diet is too heavily processed-food oriented, so food quality should remain a priority alongside the numbers.

For accurate macro tracking: (1) Use a food scale, measuring by weight (grams) is more accurate than cups/tablespoons, which can be off by 20-50%. (2) Use a macro tracking app (MyFitnessPal, Cronometer, MacroFactor) with a barcode scanner for packaged foods. (3) Log everything including oils used in cooking, condiments, and drinks. (4) For restaurant meals, estimate conservatively (most restaurants underestimate portions). (5) Check the raw weight of proteins, as cooked weight varies significantly (chicken loses 25-30% of weight when cooked). Tracking accuracy matters more for the first 4-6 weeks to develop an intuitive sense of food portions.

Yes, but it requires more planning, particularly for protein. Plant protein sources are typically less protein-dense per gram of food and often less bioavailable (lower DIAAS scores). High-protein plant sources: soy products (tofu, tempeh, edamame), seitan (wheat gluten), legumes (lentils, chickpeas, beans), quinoa, and plant-based protein powders (pea, soy, hemp). Vegan athletes should target the higher end of protein recommendations (2.0-2.4g/kg) to compensate for lower bioavailability. Creatine supplementation is also recommended for vegans/vegetarians as dietary creatine comes exclusively from animal products, and deficiency impairs training performance.

Recalculate every 4-8 weeks or whenever body weight changes by more than 5 lbs (2.3 kg). As you lose or gain weight, your TDEE and macro targets change because a lighter body burns fewer calories at rest. Other triggers to recalculate: significant change in activity level (new job, starting/stopping a sport), age milestones (BMR decreases with age), reaching a goal and switching to a new phase (from cut to maintenance, from maintenance to bulk). Apps like MacroFactor and Carbon Diet Coach dynamically adjust targets based on real-world progress data, which is more accurate than fixed recalculation intervals.

The 2025 to 2030 Dietary Guidelines for Americans, released in January 2026, set a goal of 1.2 to 1.6 g of protein per kg of body weight a day. For a 160 lb (73 kg) adult that is about 87 to 116 g. The older RDA of 0.8 g/kg (58 g at 160 lb) is still the minimum to avoid deficiency.

The National Academies' ranges for adults are 45% to 65% of calories from carbohydrates, 20% to 35% from fat and 10% to 35% from protein. On 2,000 calories that is 225 to 325 g of carbs, 44 to 78 g of fat and 50 to 175 g of protein. Sports and weight loss plans often push protein toward the top of its range.
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