Macro Calculator
Calculate your daily calorie target and protein, carb, and fat grams. Free to use, no signup required for occasional use.
What is the Macro Calculator?
The Macro Calculator estimates your daily calorie needs and breaks them down into recommended grams of protein, carbohydrates, and fat, based on your age, weight, height, activity level, and fitness goal. It starts by calculating your Basal Metabolic Rate (BMR) — the calories your body burns at rest — using the Mifflin-St Jeor equation, a formula widely used by nutritionists and considered one of the more accurate BMR estimates for the general population. That BMR is then multiplied by an activity factor based on how active you are day to day, giving your Total Daily Energy Expenditure (TDEE), which represents roughly how many calories you burn in an average day including exercise and daily movement. From there, the tool adjusts your target calories up or down depending on whether your goal is to cut (lose fat), maintain your current weight, or bulk (gain muscle and weight), and splits those calories into a protein target based on your body weight, a moderate fat allocation, and the remaining calories as carbohydrates. This gives a practical, ready-to-use starting point for tracking macros in a food diary or nutrition app, without needing to manually run the underlying formulas yourself.
How to use it
Enter your age, current weight, and height, and select your biological sex, since these are required inputs for the BMR formula. Choose your typical activity level, ranging from sedentary (little to no exercise) up to very active (hard daily exercise or a physical job), which determines how your BMR is scaled up to your total daily calorie burn. Select your goal — cut, maintain, or bulk — which adjusts your target calories below, at, or above your maintenance level. Click 'Calculate' and the tool will display your estimated BMR, your total daily energy expenditure (TDEE), your daily calorie target based on your goal, and a gram breakdown of protein, carbohydrates, and fat to hit that target. Use the protein, carb, and fat gram figures as your daily targets in a food tracking app, and revisit the calculator every few weeks as your weight or activity level changes to keep the numbers accurate.
Frequently asked questions
What formula does this macro calculator use?
It uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR), then applies an activity multiplier to estimate your Total Daily Energy Expenditure (TDEE) before adjusting for your goal.
How is my protein target calculated?
Protein is calculated based on your body weight — roughly 1.8 grams per kilogram for maintaining or bulking, and a slightly higher target for cutting, which helps preserve muscle mass in a calorie deficit.
Should I eat exactly these numbers every day?
Treat these as a solid starting point rather than a rigid rule. Individual metabolism varies, so track your actual weight trend over a few weeks and adjust calories up or down if you're not seeing the expected progress toward your goal.
Is this calculator a substitute for advice from a doctor or dietitian?
No. It provides a general estimate based on standard formulas and is not personalized medical or clinical nutrition advice. If you have specific health conditions or dietary needs, consult a doctor or registered dietitian.