How Many Calories Should I Eat Per Day? 4 Ways To Calculate

Any of us either lose or gain weight, or keep track of the results we have achieved through dieting or hard workouts. But one way or another, every one of us has asked the question, “How many calories should I eat per day?” when we start out one way or another.

I agree that there are many apps that will easily answer this question these days.  But I decided to break down in detail what our daily diet should consist of, how to calculate the necessary calories, based on many factors that are individual.
After reading this article, it won’t be difficult for you to create an individual diet, understand how many calories per day you need to consume, and correctly distribute the necessary macronutrients in your diet based on your goals and individual characteristics.

How Many Calories Should I Eat Per Day: Time-Tested Ways

What is a calorie?

Calories are the amount of energy that can be obtained from proteins, fats, carbohydrates, vitamins, micro- and macronutrients. The body uses the energy obtained for movement and vital functions or stores it as fatty tissue.

The unit for measuring the energy content of 100 grams of food is kilocalories (kcal) or kilojoules (kJ). Kilocalories are also called food calories, so often the calories are indicated in calories, without the prefix “kilo-“. If we are talking about semi-finished products, the nutritional value is given on the basis of the caloric value of 100 grams of the original product.

The final caloric value of the finished dish is influenced by the ingredients used and the cooking method. Calculate the caloric value in such a case should be summing up the nutritional value of all components.

Calorie calculation is made depending on the goal (weight loss, maintenance, weight gain), gender, age, physical activity and other factors.


how many calories should i eat per day
how many calories should i eat per day

The calculation of daily calories begins with calculating the basal metabolic rate (BMR), which is the amount of energy the body needs to sustain life processes. The human body, even at rest, constantly consumes calories for breathing, digestion, circulation and other physiological processes. The daily caloric intake must be higher than the BMR, otherwise the body will not be able to function properly.

The level of basal metabolism can be determined by two methods: direct and indirect.
The direct method is performed in the laboratory using a calorimeter. But this method is not available to a wide range of people.
Indirect method implies calculation of basal metabolic rate by a special formula. To date, there are several basic methods of calculation. Here are the main of them.

how many calories should i eat per day

The formula was derived by American physiologist Francis Gano Benedict and botanist James Arthur Harris at the beginning of the last century, but is still relevant today. It has a margin of error of about 5%.

how many calories should i eat per day

The result is the daily norm of calories the body needs for normal functioning. To calculate how many calories you need to consume to maintain your weight, you need to multiply this figure by the physical activity factor:

  • 1.2 – minimal (sedentary work, no physical activity);
  • 1.375 – light (training at least 20 min 1-3 times a week);
  • 1.55 – moderate (training 30-60 min 3-4 times a week);
  • 1.7 – high (training 30-60 min 5-7 times a week; heavy physical work);
  • 1.9 – extreme (several intense workouts per day 6-7 times a week; extremely hard work)

Mifflin St Jeor Equation

The method for calculating daily calories was developed by nutritionists under the direction of doctors Mifflin and St. Jeor. The formula was derived relatively recently, but today it is the most accurate. It helps to calculate the required number of kcal for a person between the ages of 13 and 80.

Simplified version! Be sure to take physical activity factor into account.

For women: (10 x weight [kg]) + (6.25 x height [cm]) – (5 x age [y]) – 161

For men: (10 x weight [kg]) + (6.25 x height [cm]) – (5 x age[y]) + 5.

how many calories should i eat per day

World Health Organization (WHO) Formula

The World Health Organization gives recommendations on how to calculate the daily caloric intake:

For women 18 to 30 years old (0.062 x weight[kg] + 2.036) x 240 x CFA

For women 31 to 60 years of age (0.034 x weight[kg] + 3.538) x 240 x CFA

For women over 60 years of age (0.038 x weight [kg] + 2.755) x 240 x CFA

For men 18 to 30 years old (0.063 x weight [kg] + 2.896) x 240 x CFA

For men 31 to 60 years old (0.484 x weight [kg] + 3.653) x 240 x CFA

For men over 60 years of age (0.491 x weight [kg] + 2.459) x 240 x CFA

Where CFA is the coefficient of physical activity:
1 – low
1.3 – medium
1.5 – high

how many calories should i eat per day

Katch-McArdle calorie calculation formula

This method of calculation is based on the amount of fat tissue in the body (we wrote about how to measure it in the previous article). The formula does not contain data about height, age and sex, because it is assumed that they have been taken into account when calculating the percentage of fat.

BMR = 370 + (21.6 x Lean Body Mass[kg])

It is also possible to calculate your BMR using this formula if you know:

Your body fat percentage, because then lean body mass can be calculated as follows:

LBM = (Weight [kg] x (100 – Body Fat %) / 100

Your weight and height to estimate your lean body mass using the Boer formula:

LBM (men) = 0.407 x weight [kg] + 0.267 x height [cm] – 19.2

LBM (women) = 0.252 x weight [kg]+ 0.473 x height [cm]– 48.3

how many calories should i eat per day

Let’s start counting calories with all the data.

Step 1: Calculate your basal metabolism: Choose any of the formulas we liked (A).


Step 2: Consider activity. Multiply the number in the first formula (A) by the activity factor:
– sedentary lifestyle: A*1.2
– 1 to 3 workouts per week: A*1.375
– 3 – 5 moderate workouts per week: A*1.55
– heavy workout schedule 6 to 7 workouts per week: A*1.725
– very heavy schedule, two workouts per day: A*1.9 .

We get figure B!


Step 3. Calorie deficit (weight loss 5-20%),  calorie gain – surplus (5-20%). To lose weight, you need to create a calorie deficit. The figure obtained in step 2 is the calories to maintain the shape we have now.

Assume that we want to lose weight – we need to reduce the calories by 5%, 10%, 15% or 20% (no more than 20%!). Subtracting 20% will give us our daily caloric intake for WEIGHT LOSS.

Carbs, Fats, Protein in Calorie Counting

Effective weight loss is not only about maintaining a daily calorie intake, but also about the proper distribution of proteins, fats and carbohydrates. A balanced diet in terms of the ratio of Fats and Carbohydrates will look as follows:

how many calories should i eat per day

For weight loss: 30-35% protein, 30-35% fat, 30-40% carbohydrates;
For weight maintenance: 25-35% protein, 25-35% fat, 40-50% carbohydrates;
For gaining weight: 35-40% protein, 15-25% fat, 40-60% carbohydrates.
With this distribution of macronutrients in the diet, the body receives sufficient nutrients and vitamins.

Don’t forget that all formulas for calculating daily calories may have errors. They do not take into account the percentage of digestion of food, the state of health, metabolic rate and other factors. Even a diet compiled by a specialist may not work in a particular case due to the individual characteristics of the person. In the process of building a beautiful strong body, you should listen to your feelings and change the diet and the ratio of macronutrients if necessary.

As mentioned earlier, the caloric deficit is 15 to 20 percent. This is the optimal range. Creating a larger deficit makes no sense and is dangerous to your health. If the deficit is more than 20%, the body will be stressed and any healthy weight loss is out of the question.

You can make the deficit less than 15%, it will have no effect on your health, the only thing it can affect is the time it takes you to lose weight.

Calculation of Carbohydrate, Fats and Protein Ratios

In order to get rid of extra pounds, they use a formula according to which the optimal ratio of carbs, fats and proteins is:


25% protein;
30% fats;
45% carbohydrates.

Such a diet, based on foods that contain a lot of protein, helps quickly get rid of extra pounds. In order that a high-protein diet does not harm the body, provoking the development of chronic diseases, stick to such a diet should not be more than three to four weeks. After this period of time the amount of protein should be reduced, increasing the amount of products containing carbohydrates.


To maintain weight, depending on the intensity of physical activity, the optimal ratio of carbohydrates, fats and proteins is:

15-18% protein;
30% fat;
Carbohydrates 52-55%.


Important. If the goal is to get rid of extra pounds, there should be more protein foods in the diet, reducing the amount of foods rich in carbohydrates. It is important to remember that fast carbohydrates, consumed uncontrollably, are the reason for gaining excess weight.

To determine what is the optimal amount of carbohydrates, fats and proteins, the daily caloric intake is determined. Then you determine what the ratio of carbohydrates, fats and proteins should be in percentages and grams.


For example: The daily caloric intake is 1800 kcal.

The daily norm of protein is 450 kcal, which is 25% of 1800 kcal, fats should be 540 kcal (30% of the daily norm of calories) and и 810 kcal, respectively 45% of 1800 kcal.

Having determined the percentages of carbohydrates, fats and proteins, it remains to determine their amounts, measured in grams:
The amount of proteins, according to the example, should be 109.8 grams: 450 kcal÷4.1;
number of fats: 58.1 grams (540÷9.3)
carbohydrates must be at least 197.6 grams (840÷810).


This is how you can calculate the amount of macronutrients you need in your healthy diet. Don’t forget that calorie counts and the right distribution of macronutrients are not the only things to consider when you start a healthy diet.
You also need to consider when to take your meals. I wrote about this in a recent post Meal Schedule: When Should You Eat 3 Main Meals. Please read it, you will find a lot of useful information on your way to a slim and beautiful body.

1 thought on “How Many Calories Should I Eat Per Day? 4 Ways To Calculate”

  1. Hi! Thank you for such useful information! I finally found what I was looking for in one place 🙂 Please keep writing more posts!

Leave a Comment

Your email address will not be published. Required fields are marked *