Macro Calculator — FAQ

"Macros" are macronutrients — protein, carbohydrates, and fat — the three nutrients that provide the calories (energy) in your food. Each provides a set amount of energy per gram: protein and carbs about 4 kcal, fat about 9 kcal.

You provide a calorie amount — either entered directly or pulled from your estimated maintenance calories — and choose a protein/carb/fat split. The tool multiplies your calories by each percentage, then divides by the energy per gram (4 for carbs and protein, 9 for fat) to give grams of each macronutrient. For example, 2,000 kcal at 40% carbs / 30% protein / 30% fat gives 200 g of carbs, 150 g of protein, and approximately 66.7 g of fat.

Yes, it's completely free with no sign-up, downloads, or limits. Use it as often as you like.

No — and that's intentional. This is an educational reference that shows how a calorie figure divides into macros. It doesn't prescribe a calorie target for weight change. Individual targets should be set with a registered dietitian or physician.

Yes. Choose from common presets — Balanced (40% carbs / 30% protein / 30% fat), Higher-Protein (30% carbs / 40% protein / 30% fat), or Low-Carb (20% carbs / 35% protein / 45% fat) — or select Custom and enter your own percentages for protein, carbs, and fat. They simply need to add up to exactly 100%.

There's no single right answer — it depends on the person, their activity, preferences, and any medical needs. The presets reflect common general-population ratios, but a registered dietitian or physician can advise what's appropriate for you specifically.

You can type in any calorie amount, or enable the "Use estimated maintenance calories" option. That shows a built-in TDEE estimate based on your height, weight, age, sex, and activity level — using the same Mifflin-St Jeor or Harris-Benedict formula as the TDEE Calculator. It's a general estimate, not a prescription.

No. Your inputs are processed directly in your browser and are never stored or sent to a server, keeping your information completely private.

Yes, the tool is fully responsive and works on smartphones, tablets, and desktops, with the layout fitting the screen without overflow.

No. This is a reference for understanding macros, not medical or dietary advice. Please consult a registered dietitian or physician before making any significant change to your diet or nutrition — especially if you have a health condition, are pregnant, or are managing a medical issue. If you ever find yourself preoccupied with food or restriction, consider reaching out to a qualified professional for support.