The number of calories a person burns each day varies depending on a person’s weight, height, sex, and activity levels. One way of calculating a person’s daily calorie usage is the Harris-Benedict formula. This involves multiplying a person’s basal metabolic rate (BMR) by their average daily activity level.

To lose weight, a person must burn more calories than they take in, creating a calorie deficit. But, to do this, they need to know how many calories they burn each day.

In this article, we take a look at how someone can work out how many calories they burn in a day.

## What is a calorie?

Most people think of calories as only having to do with food and weight loss. However, a calorie is a unit of heat energy. A calorie is the amount of energy that is needed to raise 1 gram (g) of water by 1°C.

This measurement can be applied to lots of different energy-releasing mechanisms outside of the human body. For the human body, calories are a measure of how much energy the body needs to function.

Food contains calories. Different foods have different calorie counts, meaning that each food has a different amount of potential energy.

There are three basic types of foods that make up all the food that humans eat: carbohydrates, proteins, and fats. These three different types of food have varying amounts of potential energy per gram.

The calorie breakdowns per g for each food type are as follows:

• Carbohydrates: 4 calories per g
• Proteins: 4 calories per g
• Fats: 9 calories per g

## Calculating daily calorie burn

Being able to work out how many calories are burned each day is essential to any person looking to maintain, lose, or gain weight.

Knowing what factors contribute to calorie burning can help a person alter their diet or exercise program to accommodate the goal.

An accepted method to calculate how many calories a person burns each day is the Harris-Benedict Formula.

Originally developed in the early 20th century, it was revamped in 1984, 1990, and, more recently, in 2023 to help improve its accuracy.

The Harris-Benedict formula is a relatively simple process in which a person multiplies their basal metabolic rate (BMR) by their average daily activity level.

BMR is the number of calories a person burns by simply existing. BMR varies based on age, sex, size, and genetics. To calculate BMR, a person uses meters (m) for height, kilograms (kg) for weight, and years for age in the following formulas:

• For men: (9.65 × weight in kg) + (573 × height in m) – (5.08 × age in years) + 260
• For women: (7.38 × weight in kg) + (607 × height in m) – (2.31 × age in years) + 43

The results of the BMR calculation are then used to multiply against the average daily activity of the person. Points are awarded based on how active a person is.

Points for activity levels are as follows:

• 1.2 points for a person who does little to no exercise
• 1.37 points for a slightly active person who does light exercise 1–3 days a week
• 1.55 points for a moderately active person who performs moderate exercise 3–5 days a week
• 1.725 points for a very active person who exercises hard 6–7 days a week
• 1.9 points for an extra active person who either has a physically demanding job or has a particularly challenging exercise routine

When the BMR is calculated and the activities points are determined, the two scores are multiplied. The total is the number of calories burned on an average day.

For example, to calculate how many calories a 37-year-old, 6-foot-tall, and 170-pound man who is moderately active burns, the formula would look like:

(66 + (6.2 x 170) + (12.7 x 72) – (6.76 x 37)) x 1.55 = 2,766 calories/day

This figure shows that a man of this age, height, weight, and activity level can consume 2,766 calories and maintain his current weight. He could increase or decrease weight by consuming more or less than this amount over the course of several days.

For those who do not wish to make the calculations themselves, there are a range of calorie calculators available online. Most use a similar formula to work out calories burned.

A doctor or nutritionist should also be able to help people work out how many calories they burn each day.

## Factors affecting calorie burn

Many factors affect how many calories a person burns each day. Some of the factors that influence daily calorie burn are not in a person’s control, while others can be changed.

These factors include:

• Age: the older a person is, the fewer calories burned per day.
• Sex: men burn more calories than women.
• Amount of daily activity: those who move more burn more calories.
• Body composition: those with more muscle burn more calories than those who have less muscle.
• Body size: larger people burn more calories than smaller people, even at rest.
• Thermogenesis: this is the amount of energy the body uses to break down food.
• Pregnancy and breastfeeding: pregnant and breastfeeding women burn more calories than non-pregnant women.

## Calories burned by exercise or activities

Calorie counts for exercise and activity will vary from person to person. Age, sex, body type, and size influence how many calories an individual will burn doing a physical activity.

In general, more intense or strenuous activity will burn more calories than lighter-effort exercise.

The following calorie counts are based on a 155-pound person doing the following exercise or activity for 30 minutes:

 Activity Calories burned aerobics 211 stationary bike (light effort) 176 dusting 70 gardening 176 hiking 211 jogging 247 mowing the lawn (no riding mowers) 141 shoveling snow 211 tennis (singles) 282 brisk walking 141 weightlifting 106 yoga 141

Anyone who wants to figure out how many calories they burn can input their statistics into a calorie calculator and find personalized results.

## Weight-loss tips

People looking to lose weight should try to create a calorie deficit by following these tips:

Losing weight can be very tough to do. Understanding how many calories an individual’s body burns per day and what to do to increase daily calorie burn is the key to success.

Below are some commonly asked questions about how many calories a person can burn in a day.

### How many calories do you need to lose a pound?

The number of calories a person needs to consume to lose a pound will vary depending on their weight, height, sex, and activity levels.

That said, on average, a female should eat 1500 calories or less to lose one pound per week. Meanwhile, the average male should eat 2000 calories a day if he wants to lose one pound per week.

### How many calories do you burn a day without trying?

A person’s body is always burning calories. In fact, the majority of a person’s daily calorie burn is just for basic body functions like breathing, circulating blood, and building cells and occurs without trying. This is known as resting metabolic rate (RMR).

This RMR represents the major portion of energy expended during the day and can range from less than 1200 to more than 3000 calories a day.

### How can I tell how many calories I burn a day?

An accepted method to calculate how many calories a person burns each day is the Harris-Benedict Formula.

This involved a person multiplying their basal metabolic rate (BMR) by their average daily activity level.

### How many calories should be burned daily to lose weight?

To lose weight, a person must burn more calories than they take in.

A calorie deficit of 500–750 calories per day has been used for weight loss and is recommended by many obesity societies and guidelines.

## Summary

Understanding and managing daily calorie burn is crucial for individuals aiming to maintain, lose, or gain weight.

The Harris-Benedict Formula, a widely accepted method, calculates calorie expenditure by multiplying basal metabolic rate (BMR) with daily activity level.

Factors that influence daily calorie burn include age, sex, activity level, body composition, size, thermogenesis, and life stages like pregnancy.

Adopting a calorie deficit, maintaining a healthy diet, getting adequate sleep, and drinking plenty of water are some ways a person can attempt to lose weight.