Macro Calculator
Calculate your daily protein, carbohydrate, and fat targets using the Mifflin-St Jeor equation — the gold standard for estimating calorie needs.
Try the calculator →Calculate Your Macros.
Reach Your Goals.
Free macro calculator backed by nutritional science. Get personalized protein, carb, and fat targets based on your body, goals, and activity level.
Science-backed formulas
Used by 50,000+ people
No email required
Evidence-Based Nutrition Tools
Built on peer-reviewed research, not trends or fads.
Educational Content
Learn the fundamentals of macronutrients, how they impact your body, and how to apply them to your specific goals — backed by research.
Read the guide →How Our Calculator Works
We use scientifically validated formulas to calculate your nutritional needs.
- Calculate Your BMR
We use the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate — the calories your body burns at rest.
- Adjust for Activity
Your total daily energy expenditure (TDEE) is calculated by multiplying your BMR by an activity factor.
- Apply Your Goal
Whether you're cutting, bulking, or maintaining, we adjust your calories and distribute them across optimal macro ratios.
- Get Your Targets
Receive personalized daily targets for protein (g), carbs (g), and fats (g) to support your goals.
Trusted by Thousands
Real results from real people using evidence-based nutrition.
★★★★★
"Finally, a macro calculator that actually explains the science behind the numbers. Lost 15 lbs in 8 weeks by following my custom targets."
★★★★★
"The articles are incredibly detailed yet easy to understand. I learned more here than from months of random YouTube videos."
★★★★★
"Love that it's free and there's no pushy sales. Just solid information backed by research. This is what the internet should be."
Why Trust Macronutrients.com?
Science-Backed Methods
Our calculations are based on validated research, including the Mifflin-St Jeor equation, Harris-Benedict equation, and macro distribution studies from peer-reviewed journals.
No Conflicts of Interest
We don't sell supplements, meal plans, or coaching. This site exists to provide free, unbiased nutritional information.
Transparent Methodology
We cite our sources, explain our formulas, and show our work. If you want to verify the math, you can.
Regularly Updated
We review and update our content as new research emerges. Every article shows when it was last updated.
Featured Articles
Evidence-based guides to help you master macros.
What Are Macronutrients? Everything You Need to Know
Learn what macronutrients are, why they matter, and how protein, carbs, and fats fuel your body. The ultimate beginner's guide to understanding macros.
Sarah Chen 
Macros for Weight Loss: The Complete Guide to Losing Fat
Learn the best macro ratios for weight loss, how to calculate your fat loss macros, and the science behind why tracking macros beats calorie counting.
Sarah Chen 
Counting Macros for Beginners: The Complete Starter Guide
New to counting macros? This beginner-friendly guide walks you through everything step-by-step — from calculating your macros to surviving your first week of tracking.
Jessica Williams 
Free Macro Calculator | Calculate Your Macros in 60 Seconds
Use our free macro calculator to find your ideal protein, carb, and fat intake. Get personalized macros for weight loss, muscle gain, or maintenance.
Sarah Chen 
Carbohydrates Explained: Simple vs Complex, How Much You Need
Confused about carbs? This guide explains what carbohydrates are, simple vs complex carbs, how many you need, and the best sources for your goals.
Dr. Michael Torres 
What is Protein? The Complete Guide to the Most Important Macronutrient
Protein explained simply: what it is, why it matters, how much you need, and the best sources. Your complete guide to the most important macronutrient.
Dr. Michael Torres