Calorie Calculator and Macro Calculator — The Complete Guide to Setting Your Macros the Right Way

Table of Contents

• Highlights
• What is a calorie calculator?
• Using a BMR Calculator to Find Your Basal Metabolic Rate
• From BMR to TDEE: Using a TDEE Calculator
  • Muscle Gain (Calorie Surplus)
  • Fat Loss (Calorie Deficit)
  • Maintenance
• What is a macro calculator?
  • Overview of the Three Primary Macronutrients
  • How to Calculate Macronutrient Goals
• Conclusion: Combining Your Calorie and Macro Goals
• Glossary

If you’re searching for a calorie calculator or a macro calculator, you’re in the right place. This guide shows you exactly how to set science-backed calorie and macronutrient targets, then turn those numbers into meals you enjoy. You’ll also get instant access to a free macro calculator and a food database that shows calories and macros for thousands of foods.

Highlights

• Free calorie and macro calculator: Calculate Your Calorie and Macro Targets
• AI-powered meal planning (start free): Create Your Meal Plan

What is a calorie calculator?

While we have developed a free online calorie calculator available at https://app.iifym.fit that simplifies this entire process, we want to explain the science behind this and other calorie estimators so you can be better informed and make any necessary adjustments for your personal situation.

A calorie calculator estimates how many calories you burn daily. This number, often referred to as your Total Daily Energy Expenditure (TDEE), depends on several factors, most notably biological sex, age, weight, height, and activity level. Below, we describe how each of those factors affects your calorie burn. While there are obvious exceptions for each factor, they are true at a population level:

• Sex: Men typically burn more calories than women due to a variety of factors, chief among which is greater muscle mass. Muscle is metabolically expensive, meaning it requires a lot of calories to maintain, use, and grow. The average man has around 73 pounds of muscle compared to 46 pounds in women—a 36% greater total muscle mass.
• Age: Younger people generally burn more calories than older adults, primarily due to differences in muscle mass, cellular activity, and hormonal metabolism.
• Weight: Generally, individuals with a higher body weight tend to have a higher total daily energy expenditure (TDEE) compared to those with a lower body weight. This is because a larger body mass requires more energy to maintain basic bodily functions (basal metabolic rate). Also, heavier people tend to have more overall muscle mass, and as we previously discussed, muscle is metabolically expensive.
• Height: Taller people burn more calories primarily because height is strongly correlated with body size, organ mass, and total metabolic tissue, all of which raise basal and total energy expenditure.

Using a BMR Calculator to Find Your Basal Metabolic Rate

Using all of these combined factors, you can estimate your BMR (Basal Metabolic Rate), which is the minimum number of calories your body needs to function at a basic level. A variety of equations exist, but the most common and scientifically validated formula is the Mifflin-St Jeor equation, which is what most online metabolic rate calculators use:

• Men: BMR = 10 * weight(kg) + 6.25 * height(cm) – 5 * age(yrs) + 5
• Women: BMR = 10 * weight(kg) + 6.25 * height(cm) – 5 * age(yrs) – 161

So in my own case, as a 5 foot 10 inch tall (177.8 cm) male who is 27 years old and weighs 167 pounds (75.75 kg), my BMR would be calculated like this:

• BMR = 10 * 75.75 + 6.25 * 177.8 – 5 * 27 + 5 = 1738.75

You can follow a similar calculation to calculate your own BMR.

From BMR to TDEE: Using a TDEE Calculator to Calculate your Calorie Goal

While we have estimated our BMR with a basal metabolism calculator, that is only a piece of the puzzle. Your BMR gives you the bare minimum number of calories needed to keep your body functioning; you will always burn more calories than that due to the physical activity you perform. An increased activity level leads to greater calorie burn because physical movement raises the body’s energy demands for muscle contraction, oxygen delivery, and cellular recovery. This process draws upon stored chemical energy in the form of adenosine triphosphate (ATP), which must be continually replenished through metabolic pathways that consume calories.

Physical activity runs the gamut from simple walking to training for an Ironman, and everything in between. The total number of calories you burn daily is called Total Daily Energy Expenditure, or TDEE. A good TDEE calculator will take your BMR and multiply it by an activity multiplier.

To get your TDEE calculation, you multiply your BMR by an activity multiplier depending on your lifestyle:

Activity Level	Description	Multiplier
Sedentary	Little to no exercise	1.2
Lightly active	Light exercise/sports 1-3 days/week	1.375
Moderately active	Moderate exercise/sports 3-5 days/week	1.55
Very active	Hard exercise/sports 6-7 days/week	1.725
Extremely active	Very hard exercise/sports & physical job	1.9

Therefore, continuing my own example, my BMR was calculated to be about 1,739 calories per day. To calculate my TDEE, I would take my BMR of 1,739 calories and multiply it by the appropriate activity multiplier. I do about 45 minutes of intense weightlifting 5 days a week, and one HIIT cardio workout one day per week. Therefore, I would multiply my BMR of 1,739 by 1.725 (hard exercise/sports 6-7 days a week), yielding the calculation below:

• TDEE = 1739 * 1.725 = 3,000 calories/day

Therefore, my TDEE is approximately 3,000 calories per day. This means that if I were to eat 3,000 calories, on average, I would expect my weight to remain stable.

Now that we have determined how many calories we burn daily, we can adjust that number based on our fitness goal. Our fitness goal can fall into one of three categories:

Muscle Gain (Calorie Surplus)

To gain muscle, you need to eat more calories than your TDEE, which is known as a calorie surplus. A typical starting point is a 5–10% surplus.

In my personal example, I am in a bulking cycle (gaining muscle). Therefore, I would take my TDEE (calculated as 3,000 calories) and multiply it by 1.05, as shown below:

• Calorie Target = TDEE * 1.05 = 3,000 * 1.05 = 3,150 calories/day

This would be my starting point. If my weight gain starts to stagnate (i.e., I am gaining less than 0.25 pounds per week), I increase my calorie intake by about 100 calories, wait a few weeks, and reassess.

Fat Loss (Calorie Deficit)

To lose fat, you must consume fewer calories than your TDEE. This is called a calorie deficit. To quickly, sustainably, and safely lose fat, you should aim to consume between 20–25% fewer calories than your TDEE.

To use my own numbers as a concrete example, if I wanted to lose fat, I would take my TDEE (calculated as 3,000 calories) and subtract 20%, as shown below:

• Calorie Target = TDEE * 0.8 = 3,000 * 0.8 = 2,400 calories/day

Again, if my weight loss starts to slow down (i.e., I’m losing less than 1 pound per week), I decrease my calorie intake by about 100 calories, wait a couple of weeks, and reassess.

Maintenance

To maintain your current weight, you should aim to eat at or very close to your calculated TDEE. Therefore, in my own personal example, I would eat at my TDEE (3,000 calories) to maintain my current weight. You might consider a maintenance diet once you have achieved your overall physique goals or when you simply want a break after an intense cutting or bulking cycle.

What is a macro calculator?

A macro calculator, or macronutrient calculator, helps you determine the optimal distribution of the three key macronutrients (carbohydrates, proteins, and fats) in your diet. Again, we recommend simply using our free macro calculator at https://app.iifym.fit/, which will optimize both your calorie and macronutrient goals simultaneously. However, let’s break down the science behind this too!

While the fundamental question of weight loss or weight gain is determined by the calorie calculator (as discussed above), macronutrient optimization is a critical component of health and fitness.

Overview of the Three Primary Macronutrients

There are three primary macronutrients: carbohydrates, proteins, and fats. Each plays a crucial role in maintaining overall health and supporting various physiological processes within the body. Here's a brief overview of each:

• Protein: Absolutely crucial for building and repairing muscle. Also increases satiety to aid in fat loss, and boosts metabolism.
  • 4 calories/gram
  • Consume 1 to 1.2 grams of protein per pound of body weight per day. This usually works out to about 30% to 40% of overall calories consumed.
• Carbohydrates: As the body's primary and most efficient source of energy, carbs fuel intense workouts and aid in recovery.
  • 4 calories/gram
  • Consume 30% to 50% of total calories from carbs
• Fats: Plays several essential roles, including (but not limited to) supporting immune function, building cells, and supplying energy.
  • 9 calories/gram (most calorie-dense macronutrient)
  • Consume 20% to 30% of total calories from fat

How to Calculate Macronutrient Goals

First, calculate your protein goal. As previously discussed, consume at least 1 gram of protein per pound of body weight per day. Then, to figure out how many calories from protein I am consuming per day, I multiply the protein goal by 4 to convert grams to calories. These calculations are as follows:

• Protein Goal = Bodyweight(lbs) * 1 g/lb = 167 lbs * 1 g/lb = 167 grams/day
• Protein Calories = Protein Goal(g) * 4 cal/g = 167 * 4 = 668 calories/day

To calculate your carbohydrate goal, multiply your TDEE by 30% to 50% to get the number of calories from carbs, then divide that number by 4 to compute the number of grams of carbs you should consume per day. To make things concrete with my own numbers, we previously calculated my TDEE to be 3,150 calories per day. Given that I personally enjoy many foods high in carbs (such as burrito bowls, pizza, etc.), I will choose the high end of the recommended range for carbs, or 50%:

• Carb Calories = Calorie Target(cal) * 0.5 = 3,150 cal * 0.5 = 1,575 calories/day
• Carb Grams = Carb Goal (cal) / 4 cal/g = 1,575 / 4 ≈ 394 grams/day

Finally, allocate all of your remaining calories to fats by taking your TDEE and subtracting the calories from protein and carbs. Then, divide that number by 9 to determine the grams of fat you should consume per day. For me, this looks like this:

• Fat Calories = TDEE - Protein Calories - Carb Calories = 3,150 - 668 - 1,575 = 907 calories/day
• Fat Grams = Fat Calories / 9 = 907 / 9 ≈ 101 grams/day

Whew! We're finally done. You now have your exact macro targets for fat loss, muscle gain, or maintenance. For me, these numbers summarize as:

• Protein: 167 grams/day (668 calories/day)
• Carbs: 394 grams/day (1,575 calories/day)
• Fat: 101 grams/day (907 calories/day)

Conclusion: Combining your Calorie and Macro Goals

From a nutritional standpoint, you now have the foundation you need to achieve your desired physique.

Now, you could go through the long and arduous process manually calculating your calorie and macro goals, researching foods and their calorie and macronutrient breakdowns, and creating a meal plan yourself. Or, you could use our free macro calculator and meal planner tools to instantly generate a delicious, personal meal plan tailored specifically to your goals.

There are many other components to consider when it comes to optimizing your fitness, notably, an exercise program grounded in resistance training. These topics will be covered in future blog posts.

For now, happy calorie and macro goal setting!

Glossary

• Calorie: A unit of energy, representing the amount of energy stored in food or the energy the body burns through activities. It is scientifically defined as the heat energy required to raise the temperature of one kilogram of water by one degree Celsius. While the term "calorie" on food labels actually refers to kilocalories (kcal) or "large calories," it is the standard unit for measuring the energy content of food and our daily energy expenditure.

• Macro (aka macronutrient): The three main components of food that the body needs in large amounts for energy, growth, and repair. They include carbohydrates, proteins, and fats.