Macro Calculator

Mifflin-St Jeor estimates resting calories within about 10% for most adults. Treat your result as a starting point: follow it for 2–3 weeks, watch how your weight and energy trend, then adjust by 100–200 calories if needed. Individual macro needs vary. This calculator gives general guidance only and is not medical advice. Always consult your doctor or a registered dietitian before making dietary changes.

Research points to about 1.6g of protein per kilogram of body weight for active adults, and a little more, about 1.8g, if you're building muscle with strength training. That's what this calculator aims for. Mixing protein sources through the day (beans, lentils, tofu, tempeh, seitan, grains) makes it easy to reach on plants.

BMR is what your body burns at complete rest. TDEE, also called your maintenance calories, adds everything you do in a day, from walking to workouts. Your calorie target starts from TDEE, then adjusts for your goal.

Yes, with a different focus. A GLP-1 medication already lowers your appetite, so skip the calorie target and use your protein and fiber numbers as a guide. With less room on your plate, smaller meals that start with protein make those goals easier to reach. Confirm your targets with your prescriber or a registered dietitian. See GLP-1 Friendly meals.

More than most people eat, yes. That's why the build-muscle goal aims at 1.8g per kg (a range of 1.6–2.0). But protein alone won't build muscle: you also need enough total calories, carbs to train on, and regular strength training.

Simple rules of thumb like 40/30/30 apply the same percentages to any calorie total, so they can overstate or understate how much protein you actually need. Like other evidence-based methods, we start from established protein guidelines instead: we set protein from your body weight first, then split the rest of your calories between carbs and fat. That keeps protein matched to your body, not your calorie target. For the woman in our example (1,910 calories), 40% protein would be about 190g a day, nearly double the 1.6g per kg where research finds extra protein stops adding muscle benefit. With our standard settings, your split stays at or near the National Academies' ranges: 10–35% protein, 45–65% carbs and 20–35% fat. Because your protein grams stay about the same as your calories change, a bigger calorie cut means a higher protein percentage.

Your calorie target stays the same, but more of it comes from fat and less from carbs: fat rises to 40–50% of calories while your protein stays the same, so carbs drop to about a third of your calories instead of about half. In the example above (1,910 calories), carbs go from 225g to about 155g a day. It's moderately lower-carb, not strictly keto, which usually means under 50g of carbs a day. That's more fat than the 20–35% in general guidelines, and research shows it can work well for people who prefer fewer carbs. Get most of it from plant fats like nuts, seeds, avocado and olive oil rather than animal fats like butter, cheese and red meat, which are higher in saturated fat.

No. That's why we show ranges. Landing anywhere in the range most days, averaged over the week, is what moves the needle.

FireRoad meals are 100% vegan, and every one lists its calories, protein, carbs, fat and fiber, so you always know what you're eating. Use Smart Search to find meals by protein, fiber, carbs or calories, then build your day around them.

• Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure. Am J Clin Nutr, 1990.
• Frankenfield D, et al. Comparison of predictive equations for resting metabolic rate. J Am Diet Assoc, 2005.
• Hall KD. What is the required energy deficit per unit weight loss? Int J Obes, 2008.
• Morton RW, et al. Protein supplementation and resistance training: a systematic review and meta-analysis. Br J Sports Med, 2018.
• Iraki J, et al. Nutrition recommendations for bodybuilders in the off-season. Sports, 2019.
• Jäger R, et al. ISSN position stand: protein and exercise. J Int Soc Sports Nutr, 2017.
• Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet, 2016.
• Gardner CD, et al. Effect of low-fat vs low-carbohydrate diet on 12-month weight loss (DIETFITS). JAMA, 2018.
• National Academies. Dietary Reference Intakes for Energy and Macronutrients, 2005.
• US Food and Drug Administration. Daily Value for dietary fiber (28g), 21 CFR 101.9.
• USDA FoodData Central, SR Legacy (food values in the protein table).

Last updated November 2026.