Weight Gain Calculator

Created by Joanna Michałowska, PhD candidate
Reviewed by Dominik Czernia, PhD and Jack Bowater
Based on research by
Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals The American Journal of Clinical Nutrition (February 1990)See 1 more source
U.S. Department of Health and Human Services and U.S. Department of Agriculture 2015–2020 Dietary Guidelines for Americans. 8th Edition. (December 2015)
Last updated: Jun 05, 2023

The weight gain calculator helps you to estimate how many calories you need to eat to increase your weight. In the article below, you will find an explanation of how calorie calculator for weight gain works and practical tips on how to gain weight. Interested? Let's answer the question "How many calories do I need to gain weight?"!

Are you currently pregnant and looking for a tool that estimates how much weight you should gain? Be sure to check out our pregnancy weight gain calculator!

Prefer watching over reading? Learn all you need in 90 seconds with this video we made for you:

Weight gain calculator - how it works?

Let's explain how the weight gain calculator works so you can answer the question "How many calories do I need to gain weight?".

  1. Enter some details about yourself: sex, height, weight, age, and physical activity level.
  2. Enter your target weight.
  3. Choose your weight gain pace.

That's all! The calorie calculator for weight gain will do all the math for you! After entering the information mentioned above, you will find out how many calories you need to maintain your current weight and therefore the minimum amount of calories you need to gain weight.

Moreover, the graphs below the calculator will show you how your calorie intake should change week by week and how your weight will increase weekly.

Risks associated with being underweight

It's well established that too high a body mass index (if you want to learn more about it, the BMI calculator is waiting for you!) is associated with an increased risk of some diseases, including cardiovascular disease and diabetes, but is being underweight dangerous too?

Actually, it is! There are several risks associated with being underweight:

  • Malnutrition;
  • Vitamin deficiencies;
  • Osteoporosis;
  • Decreased immune function;
  • Decreased fertility; and
  • Increased risk for complications from surgery.

How to gain weight?

The answer to this question may seem pretty simple - you need to eat more calories than you burn. But this is easier said than done. If your total daily energy expenditure (TDEE) is high, it might be difficult to consume as many calories as you need. This may be the case if you are, for example, vigorously running, swimming, cycling, or training some other sports.

🙋 Do you want to calculate how many calories are you burning? We created some comprehensive tools: the TDEE Calculator and the calories burned calculator!

Here are some tips to make sure that you are consuming enough micro and macronutrients:

  • Don't skip main meals;
  • Try to include healthy, energy-dense snacks in your meal plan (e.g., nuts; oat bars);
  • Get some extra calories into your meals by adding toppings like seeds, nuts, healthy dressings, etc.;
  • If drinks decrease your appetite, don't consume them with your meal; and
  • Try to estimate how many calories you eat.

How many calories do I need to gain weight?

First of all, you need to consume more calories than your total energy expenditure. TDEE depends on many different factors, including:

  • Basal metabolism, which depends on many factors itself, including: age, sex, height, weight, fat free mass, and fat mass. You can calculate it with the BMR calculator, that uses the Mifflin-St. Jeor equation;
  • The metabolic response to the food eaten, which is the energy needed to ingest and digest food;
  • Physical activity, which can vary every day. After BMR, this is the second-largest component of TDEE; and
  • Physiological state - growth, pregnancy, lactation, etc.

Once you know how many calories you burn every day, you need to add excess calories. It is estimated that you need approximately 7000 kcal to gain 1 kg or 2 lbs in a week. This means that if you will eat an extra 1000 kcal every day, you should gain 1 kg (2 lbs) within a week.

Have you already had a look at the calorie calculator for weight gain? It estimates your individual daily energy expenditure so you'll know how much calories you need per day to gain weight. If not, just give it a try!


Can being underweight be unhealthy?

Yes, being underweight can bring certain health conditions.
Maintaining a healthy weight is crucial to having a fulfilling life. A few of the problems that could come with being underweight are:

  • Malnutrition;
  • Vitamin deficiency; and
  • Weakened immune system.

So, make sure you consume calories as per your body's needs.

How many calories should I eat in a day to gain weight?

A minimum of 7000 calories are required to increase your body weight by 1 kg. If you want to gain weight, you need to eat at least 500 to 1000 calories more than you normally would eat in a day. At this rate, you would have gained 1 kg by the end of 1 or 2 weeks, depending on your intake. Also, keep in mind that the calories you burn also impact the rate of weight gain. The more calories you burn, the slower you will gain weight.

Can I maintain my current weight without gaining or loosing any weight?

Yes, you can maintain your current weight.

The main thing to keep in mind is maintaining a balance between the calories you consume and the calories you burn. If both numbers are equal, you are more likely to maintain weight.

How fast can I gain weight?

Each body is unique; therefore, we all have a different tendency to gain weight.
A minimum of 7000 calories equals a weight gain of 1 kg. So, if you consume 1000 calories more than your typical consumption, you would have gained 1 kilogram by the end of the week.

Keep in mind that if you have a workout routine, your calorie consumption will need to be much greater as you are burning more energy.

Joanna Michałowska, PhD candidate
Personal details
Activity level
Light exercise 1-2 times/week
Target weight
Weight gain pace
Normal 0.5 kg (1.1 lb) / week
Calories to maintain weight
😋 This is the amount of calories you should eat to maintain your weight. Check the calorie intake graph below to see your recommended daily energy consumption for weight gain.
Display graphs
Calorie intake
Check out 30 similar dietary calculators 🥗
Added sugar intakeBasal energy expenditureBMR - Harris-Benedict equation… 27 more
People also viewed…

Berg balance test

Use the Berg Balance Test calculator to assess dynamic and static balance and the risk of falls.

Chilled drink

With the chilled drink calculator, you can quickly check how long you need to keep your drink in the fridge or another cold place to have it at its optimal temperature. You can follow how the temperature changes with time with our interactive graph.

Helium balloons

Wondering how many helium balloons it would take to lift you up in the air? Try this helium balloons calculator! 🎈

Oxygenation Index

Calculate the Oxygenation Index and the PaO₂ / FiO₂ ratio to measure the patient's lungs' performance, and the chances they have Acute Respiratory Distress.