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Every day, you burn calories when you move around, exercise, and go about your daily tasks.

Most female adults need 1,600–2,200 calories per day, while adult males need 2,200–3,000 calories per day. However, the amount of calories you need each day is unique to your body and activity levels (1).

Calories are important for basic bodily functions, such as:

  • breathing
  • circulating blood
  • cell processes

You also burn additional calories from everyday movements, as well as exercise, which can vary considerably from person to person. If you’ve ever wondered how many calories you burn each day, the Mifflin-St Jeor formula can help you figure this out.

This formula calculates your resting metabolic rate (RMR), also known as your resting energy expenditure, which is the number of calories your body needs to function at rest.

With one more calculation, which considers your activity levels, you can work out how many calories you need each day to maintain your current weight. Eating fewer calories than this will likely result in weight loss, while eating more calories than this will likely lead to weight gain.

This article teaches you how to calculate your calorie needs based on your health goals.

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The number of calories you should burn in a day largely depends on your personal health and fitness goals, as well as other factors like your age, sex, height, weight, and activity levels.

To lose weight

To lose weight, you must be in a calorie deficit. This means you’re either eating fewer calories than your body needs, burning additional calories, or a combination of both.

For sustainable weight loss, an ideal calorie deficit will be around 10–20% fewer calories than your total daily energy expenditure (TDEE).

Let’s say that your body needs 2,200 calories per day. A calorie deficit of 10–20% would be 1,760–1,980 calories per day (Equation: 2,200 – (2,200 × 0.1) = 1,980 or 2,200 – (2,200 × 0.2) = 1,760).

While you can achieve weight loss quicker with a larger calorie deficit, it may be difficult to sustain long term since it will likely lead to significant hunger. Your body may employ mechanisms to prevent further weight loss, such as sluggishness or a reduced metabolic rate (2, 3).

Furthermore, too large of a deficit can lead to loss of lean muscle. A mild calorie deficit paired with resistance training can help preserve lean muscle mass while also promoting fat loss (4, 5, 6).

That said, weight loss can be influenced by a variety of factors, such as age, genetics, hormones, medical conditions, and medications. Therefore, you may need to work with a healthcare professional who can develop personalized recommendations for you (7).

To maintain weight

If you’re looking to maintain your weight, you’ll want to ensure your calorie intake matches your calorie expenditure.

To figure this out, you’ll need to calculate your TDEE, which is the number of calories your body needs to sustain the weight you’re currently at.

If you notice that you’re gaining weight, this is likely a sign that you’re either consuming more calories or expending fewer calories than you intend to. If you’re losing weight, you’re liking not eating enough calories or expending too many calories.

To gain weight

If you want to gain weight, you need to be in a calorie surplus. This means that you’re either eating more calories than your body needs, expending fewer calories, or a combination of both.

As in the case of a calorie deficit, you’ll want to do this slowly to ensure it’s healthy and sustainable. A mild calorie surplus of around 10–20% will allow for slow, gradual weight gain.

If your calorie needs are 2,200 calories per day, a calorie surplus of 10–20% would be 2,420–2,640 calories per day.

While it may seem obvious to eat a very large amount of calories and limit your physical activity, this strategy isn’t ideal, as it will likely lead to excessive fat accumulation and removes the important health benefits of exercise (8).

Ideally, choose nutrient-dense foods that are higher in calories to support gradual weight gain. Examples include:

  • whole milk, yogurt, etc.
  • protein shakes
  • avocados
  • nuts, seeds, and their oils
  • rice and other whole grains
  • salmon and other oily fish
  • meal replacement drinks as a snack

If you struggle to eat large meals, you may want to eat smaller meals more frequently. You may also want to cut back on your physical activity if you’re extremely active. For example, you may wish to reduce the time, frequency, or intensity of your exercise.

In some cases, your healthcare professional may want you to gain weight quicker, so be sure to listen to their advice.

The Mifflin-St Jeor equation is an easy way to calculate how many calories you need to eat per day, and it’s considered one of the most accurate formulas. It’s adjusted based on your sex, age, height, and weight to give a personalized estimation (9).

This equation was first published in 1990 as an updated formula that better predicts a person’s energy expenditure than the previously used Harris-Benedict equation (10).

Once you calculate your resting metabolic rate (RMR), you can multiply this figure by an activity factor based on your daily activity level — ranging from sedentary to very active — to find out the number of calories you need to consume each day to maintain your weight.

The next sections will tell you how to do these calculations. If you’re looking for a quick answer, you can use our handy online calculator to do the legwork for you.

Step 1. Calculate RMR

Your RMR is the number of calories your body needs to function, and it does not include your daily physical activity and other movements. To calculate your RMR, use your sex, age, height, and weight to adjust the formula.

The formulas for calculating this number are as follows, using kilograms for weight, centimeters for height, and years for age (9).

For males, use the following equation:

  • 9.99 × weight + 6.25 × height – 4.92 × age + 5 = RMR for males

For example, a 40-year-old, 180-pound (81.6-kg), 6-foot (183-cm) tall man has a BMR of 1,767. This means that, at rest, he’ll burn approximately 1,769 calories in a day (Equation: (9.99 × 81.6 kg) + (6.25 × 183) – (4.92 × 40) + 5 = 1,767).

For females, use the following equation:

  • 9.99 × weight + 6.25 × height – 4.92 × age – 161= RMR for females

For example, a 40-year-old, 150-pound (68-kg), 5’6” (168-cm) woman has a RMR of 1,372 (Equation: (9.99 × 68 kg) + (6.25 × 168) – (4.92 × 40) – 161 = 1,372).

Keep in mind that this number calculates your RMR, or resting energy expenditure, which does not account for any movement throughout the day. You would not use this as the final number for your calorie needs.

Step 2. Work out your activity level

From there, you must figure out your activity level. The activity levels the equation uses are as follows (11):

  • 1.2, or sedentary (little to no exercise)
  • 1.375, or lightly active (light exercise 1–3 days per week)
  • 1.55, or moderately active (moderate exercise 3–5 days per week)
  • 1.725, or very active (hard exercise 6–7 days per week)
  • 1.9, or extra active (very hard exercise, training, or a physical job)

For example, a postal worker who walks all day for their job would have an activity level of 1.725depending on the length and difficulty of their route.

A desk worker who walks several times a week for exercise would have an activity level of 1.55.

Step 3. Use the full equation

Putting everything together, the Mifflin-St Jeor equation is as follows:

  • RMR × activity level = calories needed to maintain weight

A 150-pound (68-kg) female who’s extra active will need 2,611 calories to maintain their weight (Equation: 1,372 (RMR) × 1.9 (activity level) = 2,607 calories).

A 180-pound (81.6-kg) male who’s moderately active will need 2,742 calories to maintain their weight (Equation: 1,767 (RMR) × 1.55 (activity level) = 2,739 calories).

As you can see in the above examples, a person’s activity level has a lot to do with how many calories they need each day.

Many people think they need to exercise hard to burn calories throughout the day.

While exercise does burn a lot of calories, your body also burns calories while you’re doing normal daily tasks. How much you burn has to do with how much you weigh.

For example, people will burn the following number of calories in 30 minutes of doing these tasks based on their weight (12):

Task125-pound (56.7-kg) person155-pound (70.3) person185-pound (83.9-kg) person
walking at 4.5 mph150186222
cleaning the gutters150186222
mowing the lawn135167200
gardening135167200
washing the car135167200
walking at 4 mph135167200
walking at 3.5 mph120149178
playing with the kids (moderate activity)120149178
grocery shopping (with cart)105130155
cooking7593111
sitting in meetings496072
light office work455667
computer work415161
standing in line384756
reading344250
watching television232833
sleeping192328

Note that your exercise habits affect how many calories you burn at rest. While aerobic activity may burn more calories during the training session, researchers have found that resistance exercise increases resting metabolic rate for up to 14 hours after exercising (13, 14).

You can use an interactive online calculator to find out how many calories you’ll burn while doing different activities. To use it, simply input your activity, the time spent doing it, and your weight.

Yes, males and females burn calories at different rates. This is why sex is included as a variable in the equation, along with age and weight, which also affect the number of calories a person burns.

People assigned male at birth generally have less body fat than people assigned female at birth. They also tend to have more muscle mass. More muscle means the body burns a higher number of calories while at rest.

So, generally, males usually burn more calories than females overall. That said, a person’s body composition plays an important role, as do hormone levels.

Losing weight isn’t always as simple as plugging numbers into a calculator.

The most effective way to lose weight and keep it off in the long term is to follow a balanced lifestyle that includes:

  • following a well-balanced diet
  • engaging in regular exercise
  • getting adequate quality sleep
  • effectively managing your stress levels

Some people also find these tips can help when they’re trying to lose weight:

  • reading labels to learn the nutritional facts about the foods you eat
  • keeping a food diary to see what you eat in a day and identify areas for improvement
  • choosing lower calorie options when choosing foods, such as skim milk instead of whole milk, air-popped popcorn instead of chips, and thin crust pizza instead of thick crust
  • reducing processed, high calorie, nutrient-poor foods like candy, cookies, and chips
  • being mindful of portion sizes to avoid overeating
  • putting food on a plate rather than eating it straight from the bag
  • using smaller plates and bowls
  • eating slowly and chewing food thoroughly
  • waiting at least 20 minutes before going back for seconds
  • making small, sustainable changes instead of favoring a crash diet
  • wear a fitness tracker or smartwatch to monitor your activity levels

Shop for food diaries to help get you started.

And check out the best calorie counter websites and apps here.

If you’re struggling to gain or lose weight, you may want to see a healthcare professional who can provide personal recommendations.

Lose weight

If you aren’t losing weight despite increasing your physical activity and decreasing your food intake, you may want to visit your primary care professional.

They can assess your current lifestyle habits, medications you’re taking, any medical conditions, family history, and other factors that may be preventing you from losing weight.

You may also be referred to other specialists, such as a registered dietitian, who can provide a detailed assessment of your diet and give personalized suggestions to help you achieve weight loss based on your unique situation.

If an underlying hormonal condition is suspected, such as hypothyroidism, they may refer you to an endocrinologist.

Gain weight

If you can’t put on weight or are losing weight unintentionally, it’s important that you speak with your primary care professional as soon as possible. In some cases, this could be a sign of an underlying condition like hyperthyroidism or cancer.

They may also refer you to a registered dietitian who can assess your diet and provide suggestions to increase your calorie intake in a healthy way, or a physical therapist who can help you build muscle.

The amount of calories you need each day is unique to your body, lifestyle habits, and health goals.

While the average male and female need roughly 2,200–3,000 and 1,600–2,200 calories per day, respectively, your needs may differ depending on your height, weight, and activity level.

Learning how to calculate your individual calorie needs is a good way to know whether you’re on track with your health and fitness goals, such as losing, maintaining, or gaining weight.

That said, if you’re looking for personalized recommendations or struggling to achieve specific health goals, talk with a healthcare professional who can give a more thorough assessment.