How Many Calories Do I Need To Gain Weight? [Calculators Included]

Are you skinny and want to gain weight?

If so, you are not alone.

Below are two simple calculators you can use to determine how many calories you need to eat per day to gain weight.

These are the strategies I used to go from 135 lbs to 165 lbs.

Let’s dive right in.

how many calories do you need to gain weight cover image

How Many Calories Do I Need To Gain Weight?

The only way to gain weight is to enter a hypercaloric state.

This means that you must consume more calories than you are burning on a daily basis.

To calculate this, you will need to:

  • Step 1: Determine Your Basal Metabolic Rate
  • Step 2: Determine Your Total Maintenance Calories Based on Your Activity Levels
  • Step 3: Increase Your Daily Calorie Intake by 300-500 Calories Over Your Maintenance Calories

Let me show you how.

Step 1: Determine Your Basal Metabolic Rate (Calculator)

The amount of calories you burn on a daily basis is extremely complex and can be influenced by several factors.

Thankfully, there’s a quick way to determine the number of calories you burn just to stay alive, aka your basal metabolic rate.

It’s called the Harris-Benedict Equation.

Your basal metabolic rate is the number of calories that your body burns at rest and to keep your organs working.

So what’s the calculation?

For women it is: 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches) – ( 4.7 x age in years )

For Men it is : 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) – ( 6.8 x age in years )

Or, you can just use the calculator here.

Is this calculation accurate?

It’s accurate enough. There are several factors that can influence this number, but it serves as a useful baseline to start with.

Now that you have this number, we must multiply it by how active you currently are to get your adjusted basal metabolic rate.

How To Determine Your Maintenance Calories Based On Excercise

There are five activity levels:

  1. Sedentary: Very little to no physical activity besides activities of daily living
  2. Mildly active: Your work requires physical activity, or you work out 1-2 times a week.
  3. Moderately active: You exercise 3-4 times a week and engage in active work.
  4. Very active: You exercise heavily 4-6 times a week
  5. Michael Phelps status: Daily exercise activity (sometimes with 2 times a day workouts).

After you determine which activity level you fall under – here is what you multiply your BMR by:

Activity LevelMultiplication Factor
SedentaryMultiply your BMR by 1.2
Mildly ActiveMultiply your BMR by 1.35
Moderately ActiveMultiply your BMR by 1.5
Very ActiveMultiply your BMR by 1.75
Michael PhelpsMultiply your BMR by 2

For example:

Let’s say you are a 30-year-old woman.

You weigh 100 lbs at a height of 5’2 and you are mildly active individual.

  • Using the calculator above, your basal metabolic rate is 1240.
  • Next multiply this number by 1.35 since you are mildly active, which gives us 1675 calories per day for maintenance
  • In theory, you need to consume 1675 calories per day just to maintain your weight.

Again, this is just an estimate, but a useful one.

Alright, now what do we do with this number?

The Last Step: How Many Additional Calories Should You Eat Per Day To Gain Weight (Calculator)

Now you should aim to increase your daily caloric intake by ~300-500 calories per day over your maintenance calories.

You may be tempted to increase your caloric intake more to speed up the process. I highly suggest that you not do this.

You may slip up from time to time, but you should do your best to to not exceed 500 calories frequently.

Here is a simple calorie calculator you can use:

Input your current weight, the weight you want to be, and the time frame you wish to achieve it:

You must eat at this new caloric surplus every day for at least 2 weeks.

You can do this by simply increasing your serving size at every meal or adding a new meal to your daily diet.

If you have not gained ~1-2 lbs after two weeks, then adjust your caloric intake by an additional 250 calories per day and reassess.

Why You Should Not Exceed A 500 Calorie Surplus A Day

If you try to increase your caloric intake by > 500 calories a day, you may begin to struggle with consistency.

Your body, and most of all your stomach, will need some time to get used to the extra calories.

So do not rush this process!

You may notice that you will feel full more often than not, and may not want to eat as often as you need to.

The simplest way to avoid this is to keep your excess calories to a modest amount every day.

An effective (and sustainable) approach is to:

  • Increase your maintenance calories by 250 calories per day for 1-2 weeks, until you stop gaining weight
  • Then bump it up to 500 calories per day for 1-2 weeks until you stall again,
  • and so on and so forth.

The bottom line?

You must keep your caloric surplus relatively constant every single day to gain weight the right way!

How To Determine Your Current Caloric Intake

Do you have any idea how many calories you consume each day?

Most people don’t.

Thankfully, there is a convenient way to estimate this number.

This method is not super accurate by any means, but it serves as a quick guide that you can use throughout the day.

It’s the calorie control guide by Precision Nutrition.

Basically, you use your own hand to measure the amount of each macronutrient you should consume at each major meal.

  • Your fist is approximately 1 cup
  • Your cupped hand is approximately 1/2 cup
  • Your palm is approximately 3-4 ounces of food
  • Your thumb is approximately 1 tablespoon

Next, you need to understand portion sizes. Here are some general portion size guidelines:

  • You can consume 1 fist (1 cup) of vegetables per meal,
  • 1 cupped hand (1/2 cup) of carbohydrates per meal,
  • 1 palm (3-4 ounces) of protein per meal,
  • and 1 thumb (1 Tbsp) of fat per meal.

Then, you need to be able to categorize food into carbohydrates, proteins, and fats.

Not all foods will fit perfectly into one category, but here are the general guidelines.


Here is a list of the most common carbs:

Most Common Carbohydrates
Quinoa & Other Grains
Legumes (can also be classified as a protein for vegetarians)


Here is a list of the most common proteins:

Fish & Seafood
Soy (Tofu, Tempeh, Edamame)


Here is a list of the most common fats:

Most Common Fats
Nuts & Nut Butters

How To Use These Guidelines To Estimate Your Calories

Lastly, for a quick and dirty calorie count using this method, follow these general guidelines.

  • 1/2 cup of the carbohydrates listed above have approximately 100-150 calories
  • 3-4 ounces of the proteins listed above have approximately 200-250 calories (exception: tofu will have ~50-100 calories)
  • 1 tablespoon of the solid fats will have approximately 50 calories, and 1 tablespoon of the liquid fats will have approximately 100 calories.
  • 1 cup of vegetables will have a negligible amount of calories.

For any other foods that do not fall into these criteria, you will just have to look up on MyFitness Pal.

Don’t worry.

This is only temporary and you will quickly get a good sense of how many calories all types of foods have.

All you need are rough estimations.

Second Alternative: Weighing and Measuring Food

However, if you are a Type A, and you want to weigh and measure your food (like I used to do) you can get a good food scale for cheap on Amazon.

I prefer the non-electronic scale, as it’s one less electronic you have to worry about breaking or malfunctioning.

How Quickly Can You Gain Weight?

If you follow the principles I have laid out above, you can expect to gain approximately 1 – 1.5 lbs per week.

Remember, this is a long-term project. Nothing in fitness comes easy.

Do not put your health at risk and become a statistic.

Take your time and do it the healthy way!

Other Related Questions

How much weight will I gain if I eat 3000 calories a day?

If your daily maintenance calories are 2500, then 3000 calories per day might help you gain 1 lb per week.

On average, you will gain approximately 1 lb of mass for every additional 3000 calories you consume over your maintenance.

If your daily maintenance calories are below 2500, consuming 3000 calories per day will lead to faster weight gain, but in an unhealthy and likely unsustainable manner.

Is 5000 calories a day too much? (What’s the highest you can go?)

5000 calories per day will be too much for the vast majority of people.

Also, it is very difficult to consume this many calories without eating junk food.

Eating this many calories per day (especially from junk food) will make you gain excess body fat.

Moreover, you put yourself at risk of developing chronic metabolic disorders and health problems such as heart disease, high blood pressure, hyperlipidemia, and insulin resistance.

How can I gain weight fast?

Regardless of how fast you want to gain weight, the only way to do it is to consume more calories than you burn consistently. 

If you are in a rush to gain weight, then feel free to exceed your adjusted basal metabolic rate by more than 500 calories per day.  The caveat is that you must consume at least 500 calories over your adjusted basal metabolic rate every single day.

If you miss a day or two, you may have to start from scratch.

How come I don’t gain weight if I eat a lot?

Because of consistency.  You may be able to eat a lot in one sitting or in one day, but are you consistently eating a lot every single day without a day off?

Secondly, you might not be eating as much as you think.

Calculate your total caloric intake every day for a week to see how much food you are actually eating. You might be shocked.

How much protein do I need to gain weight?

Protein consumption is important for muscle protein synthesis but it is not the most important factor for weight gain.

If you are trying to build muscle, then it is important to consume anywhere from 0.7 – 1 gram of protein per pound of bodyweight every day.

This would be in addition to exceeding your adjusted basal metabolic rate by 300-500 calories per day.

How many calories do you need to gain weight as a female?

As a female, you will need to consume 300-500 additional calories over your maintenance calories every day to gain about 1 lb per week.

Use the Harris-Benedict Formula for females to calculate your basal metabolic rate, then multiply this number by your activity level to determine your maintenance calories.

What are the best weight gain foods?

There are a handful of foods that are very calorie-dense, making them the perfect option for hard-gainers.

Weight gain food #1: Homemade shakes

Shakes are very simple to make and allow you to pack on a lot of calories in a short amount of time.

Here’s how to make one that contains 300-500 calories.

  • Almond Milk (1 cup = ~50 calories)
  • Banana (1 medium= ~100 calories)
  • peanut butter (1 tbs = ~100 calories)
  • Oats (1/8 cup = ~50 calories)
  • Dates (2 = ~50 calories)
  • Chia Seeds (1 tbs = ~50 calories)
  • Plant based protein powder (1 scoop = ~100 calories)

Liquid calories are much easier to consume in large quantities than solid foods, making them the perfect weight gain food.

In order to break up all of the ingredients well, you will need a strong blender.  The one that I have been using for several years is the Nutribullet 900.

Weight gain food #2: Potatoes

The potato is a starchy vegetable that goes well with just about anything and everything. It also helps that they are high in potassium, a nutrient almost everyone needs more of.

If you like white potatoes, eat white potatoes. If you like sweet potatoes, eat sweet potatoes.

Don’t eat them in the form of french fries. Bake ˜em, boil ˜em, or instant pot ˜em.

Weight gain food #3: Nuts

Not many foods are as calorie-dense as nuts. 3 ounces or a palm-full of nuts have almost 200 calories.

These make for the perfect weight gain snack!

That’s not all.

Nuts also provide your body with a lot of essential Omega-3 fatty acids to keep your brain healthy too!

Buy a large tub and make several 3-ounce zip-lock bags to take with you on the go.

Weight gain food #4: Rice

Rice is another quick and easy way to pack on the calories.

Half a cup is 100 calories. Brown rice or white rice – it doesn’t matter.

If you want to up your game even more, you can eat quinoa.

Then, to top off the rice, you should add¦

Weight gain food #5: Legumes

Beans carry a lot of protein and fiber, making them a little-known power food.

There are numerous options to choose from black beans, kidney beans, chickpeas, split peas, lima beans etc. Half a cup contains 100-150 calories.

Weight gain food #6: Avocados

Rounding out the list is the avocado.

This fruit goes well with just about everything and packs on a great number of healthy calories. Half of an avocado is ~100 calories.

Wanna know one of my favorite meals?

Some type of rice, topped with some type of legume, and a side of avocado.

Alright, let go over a few more helpful strategies to help you gain some weight.

Effective ways to increase your appetite to gain weight

One of the biggest struggles you may face is a small appetite.

Eating a caloric surplus is hard. Most days, you may not feel like eating at all.

Here are a few simple ways to increase your appetite.

1) Eat quickly

There is a growing body of evidence that people who eat slowly wind up consuming fewer calories, which is beneficial for weight loss.

We are after the opposite effect.

Don’t scarf down your food, but don’t get distracted either.

2) Add herbs and spices to your foods

There is also research being done on how taste and flavor impact our eating habits.

In brief:

We tend to overeat hyper-palatable foods when they are full of flavor. Take a potato for example. How many plain potatoes do you think you can eat in one sitting?

Now, what if you take those same potatoes, fry them, add salt, and amazing tasting ketchup. How many of those do you think you could eat in one sitting?

You just can’t seem to put them down right?

Somehow, our bodies were designed to over-consume foods that taste really good, making them analogous to an addiction.

So what can we take from this?

Make your foods taste amazing by adding your favorite herbs and spices!

3) Build strength

The last strategy you can use to increase your appetite is to strength train and develop lean muscle mass.

Nothing makes your body hungrier for calories than a good ˜ole strength workout.

What kind of strength workout? I’m glad you asked.

The Best Way To Exercise For Weight and Muscle Gain

Any kind of physical activity has the potential to increase your appetite. This is normal, as your muscles require nutrients to rebuild themselves stronger than before.

So what is the best way to exercise for weight and muscle gain?

Strength training!

The best way to gain weight and muscle is to follow a dedicated strength that stimulates all of the major muscle groups in your body. The perfect strength program will

Our strength program covers this in extreme detail. Or you can download our template.

It’s also a good idea to not do excessive amounts of low-intensity cardio. In order to get your aerobics in, do plenty of walking!

A Quick Word On Weight Gain Supplements

One last thing I need to cover is the topic of weight gain supplements.

Do you need to use them? No.

Should you use them? No.

I used to buy these things and they are just a waste of money.

You are far better off using your hard-earned money on real food. Especially the weight gain foods I listed above.

Other Important Considerations

Why Are You So Skinny?

I used to weigh 140 lbs when I started college and I felt like a twig. I always wanted to be heavier and have some appreciable muscle size.

I am skinny because I am an ectomorph.

If you don’t know what an ectomorph is, I suggest you check out this article.

Chances are, you are skinny because you are an ectomorph.

Some would say that you have won the genetic lottery because you naturally have a slim frame, but not all ectomorphs share that sentiment.

In general, you naturally have a high metabolism, and a very difficult time gaining weight.

With that said, it is important to note that there may also be a few other reasons why you are skinny.

Medical Conditions That Can Cause You To Be Underweight

  1. Hyperthyroidism: Having too much thyroid hormone can rev up your metabolism leading to weight loss, heat intolerance, palpitations and insomnia.
  2. Type I Diabetes: You would know if you have Type I Diabetes. This is a condition where your body fails to make insulin and as a result you must inject insulin into your body. It often occurs in early life and can be seen in very skinny people contrary to Type II Diabetes.
  3. HIV/AIDS: HIV can present itself as loss of appetite, weight loss, fevers, pain and frequent infections. Make sure that you follow with your doctor regularly, and know what your HIV status is.
  4. Digestive Diseases: Any disease of the gastrointestinal tract can affect absorption of nutrients, leading to undernutrition and poor weight gain. Some of the more common conditions include Chron’s Disease or Ulcerative Colitis
  5. Cancer: The three principle signs of cancer are fevers, night sweats and weight loss. Again, make sure that you see a doctor for regular checkups.

Thankfully, it is most likely that you are skinny because you are an ectomorph, and not because of one of these conditions. Be sure to check with your doctor if you are not sure.

How To Tell If You Are Actually Underweight

So how do we define skinny?

First, let’s discuss the medical definition of being underweight. You are considered underweight if your body mass index (BMI) is under 18.5

Most people like to bash BMI as a very inaccurate representation of body profiles.

While this is certainly true in the opposite end of the spectrum (I was almost considered obese by BMI standards a couple of years ago), it has a great deal of merit in the underweight end.

If your BMI is 18.5 or close to it, then you are definitely, without a doubt, underweight.

Ok, what if your BMI is not 18.5?

There is nothing wrong with wanting to be a little heavier, or with wanting to add muscle size to your frame.

Here are some average bodyweight numbers for both men and women. If your weight is below the minimum body weight listed below, then you are skinny.

Average Bodyweight For Ectomorphic Men

HeightAverage Weight
5’4125 – 150 lbs
5’6135 – 160 lbs
5’8145 – 170 lbs
5’9155- 180 lbs
6’0165 – 185 lbs
6’2175 – 190 lbs
6’4185 – 200 lbs

Don’t forget these values are for ectomorphic men only!

Average Bodyweight For Ectomorphic Women

HeightAverage Weight
5’090 – 115 lbs
5’2100 – 125 lbs
5’4110 – 130 lbs
5’6115- 135 lbs
5’8120 – 140 lbs
5’10125 – 150 lbs
6’0130 – 160 lbs

Don’t forget, these values are for ectomorphic women only!

Even if your body weight falls below these numbers, and you are perfectly happy with your appearance, there is nothing wrong with that!

As long as you maintain a decent diet and a regular exercise routine, then you are golden. 

Final Words On How A Skinny Person Can Gain Weight

So that’s how to determine how many calories you need to gain weight.

Now we turn it over to you.

  • How many daily calories do you need to eat to gain weight?
  • How much weight do you want to gain?
  • What has worked and what hasn’t worked for you?

Comment below and let us know!


Alex Robles, MD, CPT / Brittany Robles, MD, MPH, CPT

Alex & Brittany Robles are physicians, NASM Certified Personal Trainers, and founders of The White Coat Trainer: a resource dedicated to improving the health and fitness of busy professionals using time-efficient strategies. Their advice has been featured in My Fitness Pal, Prevention, Livestrong, Reader’s Digest, Bustle, The Active Times, and more. Learn more about them here.

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