Macro Calculator

Introduction

A macro calculator helps you figure out how many grams of protein, carbs, and fat you should eat each day. These three nutrients are called macronutrients, or "macros" for short. Your body needs all three to stay healthy, build muscle, and have energy. The right balance of macros depends on things like your age, weight, height, activity level, and goals. Whether you want to lose weight, gain muscle, or just eat better, knowing your macros is a great place to start. Use this macro calculator to get a personalized daily breakdown that fits your needs.

How to Use Our Macro Calculator

Enter your personal details and preferences below, and this calculator will give you a daily calorie target along with the exact grams of protein, carbs, and fat you should eat each day.

Sex: Select whether you are male or female. This matters because men and women burn calories at different rates, which changes your macro needs.

Unit System: Choose US/Imperial (pounds, feet, and inches), Metric (kilograms and centimeters), or Other. If you pick "Other," a built-in unit converter will appear so you can convert between units like stone, meters, or inches and then apply those values to the calculator.

Age: Enter your age in years (between 15 and 100). Your body burns fewer calories as you get older, so age plays a key role in finding your correct macros.

Height: Enter your height in feet and inches if using Imperial, or in centimeters if using Metric. Your height helps the calculator figure out your base metabolic rate.

Weight: Enter your current body weight in pounds (Imperial) or kilograms (Metric). This is one of the biggest factors in determining how many calories and macros you need each day. If you're curious about how your weight compares to clinical benchmarks, you can also check out our Ideal Body Weight Calculator.

Activity Level: Pick the option that best describes how active you are on a typical week. Choices range from Sedentary (little or no exercise) all the way up to Extra Active (very hard exercise for two or more hours a day). A higher activity level means your body needs more calories and macros. If you track your cardio performance, tools like our Heart Rate Zone Calculator or VO2 Max Calculator can help you better gauge your exercise intensity.

Fitness Goal: Choose what you want to do with your weight. You can pick Lose Weight (−500 calories per day), Slow Lose (−250), Maintain (no change), Slow Gain (+250), or Gain Weight (+500). The calculator will adjust your calorie target up or down based on your choice.

Diet Profile: Select a diet style that fits how you like to eat. Options include Balanced (30/40/30 split), Low Carb, High Protein, Keto, Low Fat, or Custom. If you choose Custom, you can type in your own protein, carbs, and fat percentages — just make sure they add up to 100%.

Settings (BMR Formula): Click the Settings link to choose which formula the calculator uses to estimate your base metabolic rate. Mifflin-St Jeor is the default and works well for most people. Katch-McArdle is better if you know your body fat percentage, and Harris-Benedict is the classic formula. If you pick Katch-McArdle, a body fat percentage field will appear for you to fill in.

Body Fat % (optional): This field only shows up when you select the Katch-McArdle formula under Settings. Enter your body fat percentage (between 1% and 60%) for a more accurate calculation, especially if you are lean or athletic. If you're unsure of your body fat level, our Lean Body Weight Calculator can help you estimate your lean mass.

Once everything is filled in, click Calculate Macros to see your daily calorie target, your protein, carbs, and fat in grams, a visual breakdown chart, and a detailed table that splits your macros across 3, 4, or 5 meals per day. Click Reset at any time to return all fields to their default values.

What Are Macros?

"Macros" is short for macronutrients — the three main nutrients your body needs in large amounts every day to function properly. They are protein, carbohydrates, and fat. Every food you eat is made up of some mix of these three nutrients, and each one plays a different role in keeping you healthy.

• Protein (4 calories per gram) — Builds and repairs muscles, skin, hair, and other tissues. It also helps you feel full after eating.
• Carbohydrates (4 calories per gram) — Your body's main source of energy. Carbs fuel your brain, muscles, and organs throughout the day.
• Fat (9 calories per gram) — Supports hormone production, protects your organs, and helps your body absorb important vitamins like A, D, E, and K.

How a Macro Calculator Works

A macro calculator figures out how many grams of protein, carbs, and fat you should eat each day based on your personal details. It starts by estimating your Basal Metabolic Rate (BMR) — the number of calories your body burns at rest just to stay alive (breathing, pumping blood, etc.). Then it multiplies your BMR by an activity level to find your Total Daily Energy Expenditure (TDEE), which is the total number of calories you burn in a full day including exercise and movement.

Once your TDEE is calculated, the tool adjusts the number up or down based on your goal. If you want to lose weight, it subtracts calories. If you want to gain weight, it adds calories. Finally, it splits those calories into protein, carbs, and fat based on the diet profile you choose.

BMR Formulas Explained

There are several well-known formulas used to estimate BMR. The Mifflin-St Jeor equation is the most widely recommended by nutrition professionals today because it tends to be the most accurate for most people. The Harris-Benedict equation is an older, classic formula that works similarly but can sometimes overestimate calorie needs slightly. The Katch-McArdle formula is different because it uses your lean body mass (your weight minus your body fat) instead of just your total weight. This makes it a better choice for people who know their body fat percentage, especially athletes or very lean individuals.

Choosing the Right Diet Profile

The way you split your calories among protein, carbs, and fat depends on your goals and preferences. A balanced diet (30/40/30) works well for most people who want steady energy and overall health. A high protein split is popular for people who are building muscle or trying to keep muscle while losing fat — if you're strength training, our 1RM Calculator and RPE Calculator can help you optimize your workouts alongside your nutrition. A low carb approach can help people who feel better eating fewer starches and sugars. A keto diet is very high in fat and very low in carbs, which pushes the body to burn fat for fuel instead of glucose. A low fat split keeps fat intake minimal, which some people prefer for heart health.

There is no single "best" split for everyone. The right choice depends on your body, your activity level, your health conditions, and what you can stick with long-term.

Why Tracking Macros Matters

Counting calories alone tells you how much you're eating, but tracking macros tells you what you're eating. Two people can eat the same number of calories, but if one person eats mostly protein and vegetables while the other eats mostly sugar and oil, their results will be very different. Tracking macros helps you make sure you're getting enough protein to support your muscles, enough carbs to fuel your activity, and enough fat to keep your hormones and body working well. Pairing macro tracking with body composition metrics — such as your Waist to Hip Ratio or your score on the FFMI Calculator — gives you a more complete picture of your progress.

Tips for Using Your Results

The numbers from this calculator are a starting point, not a perfect prescription. Every person's body is a little different. Use these targets for two to three weeks, track how you feel and whether your weight is moving in the direction you want, and then make small adjustments. If you're not losing weight, try reducing your daily intake by 100–200 calories. If you're feeling tired or your workouts are suffering, you may need more carbs or more total calories. Runners and endurance athletes can use a Running Pace Calculator or Marathon Pace Calculator to align their training intensity with their nutrition plan. For personalized medical or dietary advice, always consult a registered dietitian or your doctor.

Frequently Asked Questions

What are macros in food?

Macros is short for macronutrients. They are the three main nutrients your body needs in large amounts: protein, carbohydrates, and fat. Every food you eat contains some mix of these three. Protein and carbs each have 4 calories per gram, while fat has 9 calories per gram.

How many calories should I eat to lose weight?

This calculator finds your Total Daily Energy Expenditure (TDEE) and then subtracts calories based on your goal. For steady weight loss, it subtracts 500 calories per day, which equals about 1 pound of fat loss per week. For slower weight loss, it subtracts 250 calories per day. The calculator will never set your target below 1,200 calories per day for safety.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest just to keep you alive. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor. TDEE includes all the calories you burn from exercise, walking, and daily movement on top of your BMR.

Which BMR formula should I use?

For most people, Mifflin-St Jeor is the best choice. It is the most accurate modern formula and is recommended by most nutrition professionals. Use Katch-McArdle only if you know your body fat percentage, especially if you are lean or athletic. Harris-Benedict is the classic formula and works fine but can slightly overestimate calorie needs.

How much protein do I need per day?

It depends on your goals and diet profile. On a balanced diet, about 30% of your calories come from protein. For a 2,000 calorie diet, that is about 150 grams of protein per day. If you are building muscle or trying to keep muscle while losing fat, a high protein split (40%) may be better. The calculator shows your exact protein target in grams based on your inputs.

What diet profile is best for building muscle?

The High Protein profile (40% protein, 35% carbs, 25% fat) is a good choice for building muscle. It gives you plenty of protein to repair and grow muscle tissue, plus enough carbs to fuel your workouts. Pair this with a Slow Gain or Gain Weight goal to make sure you are eating enough calories to support muscle growth.

What is the keto diet profile?

The keto profile sets your macros to 25% protein, 5% carbs, and 70% fat. This very low carb, high fat split pushes your body into a state called ketosis, where it burns fat for fuel instead of glucose. Keto can help with weight loss, but it is a strict diet that may not suit everyone.

How do I pick my activity level?

Choose the level that matches your typical week. If you sit at a desk most of the day and do not exercise, pick Sedentary. If you exercise 3 to 5 days a week at moderate effort, pick Moderately Active. If you do hard workouts 6 to 7 days a week or have a physically demanding job, pick Very Active. Be honest — picking a higher level than your real activity will give you too many calories.

Can I set my own custom macro ratios?

Yes. Select the Custom diet profile and three input fields will appear where you can type your own protein, carbs, and fat percentages. Just make sure the three numbers add up to exactly 100%. The calculator will show an error if they do not.

What does the per meal breakdown mean?

The results table splits your daily macro targets across 3, 4, or 5 meals. This helps you plan how much protein, carbs, and fat to eat at each meal. For example, if you need 180 grams of protein per day and eat 4 meals, you would aim for about 45 grams of protein per meal.

Why does the calculator show a minimum of 1,200 calories?

Eating fewer than 1,200 calories per day can be unsafe for most people. It can lead to nutrient deficiencies, muscle loss, fatigue, and other health problems. The calculator sets 1,200 as the lowest possible target to help protect your health. If your calculated number falls below this, the tool automatically adjusts it to 1,200.

Do I need to know my body fat percentage?

No, not for most calculations. Body fat percentage is only needed if you choose the Katch-McArdle formula under Settings. The default Mifflin-St Jeor formula does not require it. However, if you do know your body fat percentage, Katch-McArdle can give a more accurate result, especially for lean or athletic people.

How often should I recalculate my macros?

Recalculate your macros every 4 to 6 weeks, or whenever your weight, activity level, or goals change significantly. As you lose or gain weight, your calorie needs change too. Regular recalculation keeps your targets accurate and helps you keep making progress.

What is the unit converter used for?

The unit converter appears when you select Other as your unit system. It lets you convert between units like stone, meters, inches, kilograms, and pounds. After converting, you can click Apply to Calculator to send the converted values directly into the height and weight fields.

Is this macro calculator accurate?

This calculator uses well-established formulas (Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle) that are trusted by nutrition professionals. The results are a solid estimate, but every person's body is slightly different. Use the numbers as a starting point, track your results for 2 to 3 weeks, and adjust if needed.

What happens if I eat more fat and less carbs?

Shifting more calories to fat and fewer to carbs can help some people feel fuller and have more stable energy levels. This is the idea behind low carb and keto diets. However, because fat has 9 calories per gram compared to 4 for carbs, you will eat fewer total grams of food. The best split depends on how your body responds and what you can stick with.

Should I eat the same macros on rest days?

For most people, keeping the same macros every day is the simplest approach and works well. Some advanced athletes cycle their carbs, eating more on training days and less on rest days. If you are just starting out, stick with the same daily targets for consistency.