How Many Calories Should I Eat in a Day?

Some calorie calculators help you find out how many calories to eat every day if you want to maintain your weight. Some even help you to gain weight. But if you're trying to slim down, you might need a weight loss calculator. One that will answer the most important weight-loss question: "how many calories should I eat a day to lose weight?"

It's simple to calculate the right number of calories for weight loss, for weight gain, or for weight maintenance. Just follow these simple steps. Then, you'll know how many calories you need to eat a day to reach your goal.

Understanding Weight Loss Calculators

If losing weight is your primary goal, it's smart to use a weight loss calculator. It's a simple procedure and can even be fun and interesting—even if you're not trying to change your weight. 

How does a calorie counter work? After you input data, it uses a formula called the Mifflin St. Jeor equation to calculate your resting metabolic rate. That's the number of calories your body needs to function when it is at rest.

Then, based on your personalized lifestyle information including your sex, weight, height and age, the calculator adds the number of calories you need to fuel your body for daily activity. Finally, it either adds calories to gain weight or subtracts calories to help you lose weight. 

But what if you want your weight to stay the same? The calculator can figure out how many calories you should eat to maintain weight as well. This information is helpful for many healthy eaters. 

If you are at a healthy weight and want to maintain your body size, you should make sure that you don't eat too much or too little. For some adults, that means consuming a 2000-calorie diet.

That's the number that is referenced on the Nutrition Facts label. But many people are larger or smaller than average, or are more or less active than normal and have different calorie needs.

Using a Weight Loss Calculator

Are you ready to give the calorie calculator a try? You'll need to provide some vital information about your age, gender, height, and your current weight to get the right calorie number.

The calculator requires this data because these are factors that influence your metabolism—or the number of calories that your body needs to function. In general, men need more calories than women. Larger bodies need more calories than smaller bodies, and younger adults require more calories than older adults. 

You'll also be asked about your activity habits. If your body is more active during the day, it requires more fuel (in the form of calories). Try to be as honest as possible about your exercise and daily activity habits.

If you fudge the numbers, you won't get an accurate result.

If you're not sure how active you are during the day, keep an activity journal for a week or look at data from your fitness tracker to get a quick estimate.

Next, you'll be asked about your goals. It's important to be realistic during this step. Your goal weight may be different than an ideal weight or a perfect weight. For example, you may want to weigh 120 pounds.

But if you have struggled with your weight for most of your life and have never been lower than 150 pounds, then 120 may not be realistic at this time. You also don't want to set a goal weight that is below your healthy BMI (body mass index).

Try to set goals that you believe are attainable. Once you reach your goal, you can always set a new one. Lastly, you'll have the option to select a date when you'd like to reach your goal.

If you are trying to lose weight, a healthy rate of weight loss is 0.5 to 2 pounds per week. If you are trying to gain weight, you may be able to put on approximately 1 pound per week. 

Reaching Your Goal Weight

When you complete the calorie calculator process, you'll get a daily calorie goal. This is the number of calories you should eat each day to reach your desired weight in the time frame that you set.

If you are trying to gain weight, your daily calorie goal will include a calorie surplus. But if weight loss is your goal, a calorie deficit is factored into your final number. A calorie deficit is simply an energy shortfall. When you create a calorie deficit, you deprive your body of the fuel it needs to function.

So, your body burns stored fat (excess weight) for fuel instead. A calorie deficit occurs when you cut calories by eating less than your body needs or burn extra calories with physical activity. You can also combine diet and exercise to create a calorie deficit.

If you cut more calories, you'll lose weight faster. But it is not safe or practical to cut too many calories. Very low-calorie diets (less than 800-1000 calories per day) can backfire and should only be followed with a doctor's supervision.

Sound complicated? Let's use an example to explain. Let's say that you are a sedentary woman. That means that you don't exercise on a regular basis. The weight loss calculator may say that you need to eat 1,200 calories per day to lose weight.

But you don't think that you can cut enough food from your diet to reach that number. That's OK. You can simply add exercise to your weekly routine to account for a few extra calories. Here are a few ways you might make it work:

  • Eat 1,300 calories (100 extra) each day and add a short evening walk to your daily routine to burn the extra 700 calories each week.
  • Eat 1,400 calories (200 extra) each day and add a HIIT workout to your schedule two times per week and three 30-minute walks during the week to burn the extra 1,400 calories each week.
  • Eat 1,500 calories (300 extra) each day and add 45 minutes of moderate to vigorous exercise to your daily schedule to burn the extra 2100 calories each week.

In each of these scenarios, you've added calories to your daily food budget, but you've burned more calories with exercise to maintain the proper calorie deficit for weight loss. If you want to lose weight faster, you just add the exercise to your daily routine without adding calories to your daily diet. 

Answers to Your Questions

Still confused about using a calculator for weight loss? These are a few common questions that people looking to lose weight often ask. Here is an overview of the most frequently asked questions.

Can I Eat Whatever I Want and Still Lose Weight?

This is a tricky question. You can eat whatever you want and lose weight as long as you stay in your calorie range. Theoretically, you could eat candy bars all day and lose weight. But you probably wouldn't want to. Why? Because it would be very hard to stay in your calorie range if you don't eat nutritious foods.

Healthy foods help you to feel strong, energized, and satiated. Empty calorie foods don't provide your body with the nutrients you need to live an active, well life. And when you eat junk food, you're likely to get hungry more often and overeat as a result.

Can I Eat More If I Exercise Every Day?

If you factored exercise into the equation when you used the calculator, then you should not eat more if you exercise. Your daily calorie goal (the calculator result) has already accounted for the additional physical activity.

But if you did not factor in exercise when you used the calculator, and you added a workout session to your day, then the calories burned during exercise will increase your calorie deficit. If you don't eat back your exercise calories, the increased deficit will help you to lose weight faster.

If you do eat back the same number of calories that you burned, then you will lose weight at the same rate as indicated in your calorie calculator result. Be careful, however, it's very easy to eat more calories than you burn after exercise. This causes weight gain, not weight loss.

How Should I Count My Daily Calories?

There are different ways that you can keep track of your daily calorie intake. Many people looking to eat healthier use a smartphone app or websites like MyFitnessPal or LoseIt.

These services allow you to input the food you've eaten along with your portion size and it automatically calculates your daily calories, protein, fat, and carbohydrate intake.

There are also activity trackers, like Fitbit, which help you count daily food calories and daily exercise calories. If you're not a fan of tech gadgets, use weight loss journal. Simply write your calories in a notebook or on a daily food intake sheet to count your daily numbers.

Should I Join a Diet Program? 

There is no "best" diet for anyone because we are all so different, with different lifestyles and different needs. The diet that will work best for you is the diet you can stick to.

For some people, a do-it-yourself program is best. But others benefit from the structured approach of a commercial weight loss program. Ask yourself key questions about your lifestyle (do you cook? how much time do you have to shop for healthy food? what is your budget?) and then make a decision that fits your needs. 

Are All Calories the Same?

Even though your total calorie intake matters most for weight loss, all calories are not created equal. Calories from nutritious food sources will help you to feel full longer, provide fuel for your daily activity, and improve your well-being. So what are healthy foods? Most experts recommend that you fill your plate with:

  • Colorful vegetables like leafy salad greens, bright peppers, crunchy carrots or radishes. Experiment to find flavors that you enjoy.
  • Lean meats like chicken and fish. You may also enjoy red meat in moderation.
  • Whole grains that provide fiber such as oatmeal, whole grain bread or crackers.
  • Whole fruits rather than fruit juices or fruit-flavored snacks.
  • Nuts, seeds, and other sources of healthy fats in small servings.
  • Water instead of sports drinks, sweetened tea, or sodas.

Empty calories, on the other hand, can leave you feeling hungry, increase your cravings for food, and even increase fatigue. What are empty calories? You'll find them in processed foods that contain added sugars, trans fat, excess fat, and calories. Empty calories provide you energy but not the fiber, vitamins, and minerals you need.

Healthy Foods
  • Colorful vegetables

  • Lean meats

  • Whole grains with fiber

  • Whole fruits

  • Small servings of nuts and seeds

  • Water

Empty Calories
  • Candy

  • Fast food

  • Processed baked goods

  • Sodas

What If I Don't Lose Weight?

There are many factors that contribute to weight loss success. If you don't lose weight right away, it doesn't mean that you have failed or done something wrong. But it might mean that you need to stick to your program longer for weight loss to happen. 

Evaluate your eating and exercise habits to see if there are adjustments you can make to reach your goal. There may also be medical reasons that you can't lose weight. So talk to your healthcare provider if you've tried to slim down without success.

Your doctor may be able to refer you to a registered dietitian for personalized nutrition advice. Your doctor also may talk to you about weight loss medications or weight loss surgeries to help you lose weight.

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  1. Ndahimana D, Choi YJ, Park JH, Ju MJ, Kim EK. Validity of predictive equations for resting energy expenditure in Korean non-obese adults. Nutr Res Pract. 2018;12(4):283-290. doi:10.4162/nrp.2018.12.4.283

  2. United States Department of Health and Human Services. DIETARY GUIDELINES FOR AMERICANS 2015-2020 EIGHTH EDITION. 2015.

  3. Mcmurray RG, Soares J, Caspersen CJ, Mccurdy T. Examining variations of resting metabolic rate of adults: a public health perspective. Med Sci Sports Exerc. 2014;46(7):1352-8. doi:10.1249/MSS.0000000000000232

  4. Sumithran P, Proietto J. Safe year-long use of a very-low-calorie diet for the treatment of severe obesity. Med J Aust. 2008;188(6):366-8.