Weight Gain Calculator
Estimate how many calories you need to consume and the time it will take to gain weight using the calorie surplus calculator.
Daily Calorie Requirements:
|Maintain Current Weight:|
|Reach Goal Weight:|
Time to Reach Goal Weight
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How to Calculate a Calorie Surplus for Weight Gain
If you’re trying to gain weight, particularly muscle mass, then calculating the right calorie surplus is especially important. A calorie surplus is when you consume more calories than your body needs for daily activities.
A calorie surplus is essential for providing your body with the energy it needs to build muscle to gain weight in a healthy and sustainable way. Similar to eating fewer calories when trying to lose weight, you’ll need to increase your calorie intake to gain weight.
You can calculate a calorie surplus using a simple formula.
Calorie Surplus Formula
A calorie surplus is equal to calorie intake minus calories burned.
calorie surplus = calorie intake – calories burned
You should do this in a safe and calculated manner to avoid unhealthy weight gain or the development of unhealthy eating habits. You can calculate the ideal calorie surplus in a few steps.
Step One: Calculate Your Basal Metabolic Rate
Your basal metabolic rate (BMR) is the number of calories your body needs to maintain basic functions, such as breathing, heart rate, and body temperature, at rest. There are several formulas to calculate your BMR, such as the Mifflin-St Jeor and Harris-Benedict equations, which account for your age, gender, weight, and height.
Mifflin-St Jeor BMR Formula
BMR = (10 × weight [kg]) + (6.25 × height [cm]) – (5 × age [years]) + 5
BMR = (10 × weight [kg]) + (6.25 × height [cm]) – (5 × age [years]) – 161
Step Two: Calculate Your TDEE
You also need to account for your physical activity level, which approximates the number of additional calories you burn through exercise and daily activity. You burn more or less energy the more or less active you are, and thus, require more or fewer calories based on your activity level.
This is known as your total daily energy expenditure (TDEE), and you can calculate it using a formula.
TDEE = BMR × activity factor
Thus, your TDEE is equal to your BMR times the activity factor corresponding to your general level of activity. The table below shows the activity factor corresponding to various levels of exertion:
|Level of Activity||Example||Activity Factor|
|Sedentary||Little to no exercise, such as a desk job with no additional physical activity||1.2|
|Lightly Active||Light exercise 1-2 days/week||1.375|
|Moderately Active||Moderate exercise 3-5 days/week||1.55|
|Very Active||Hard exercise 6-7 days/week||1.725|
|Extremely Active||Hard daily exercise and physical job or two times a day training||1.9|
Step Three: Set Your Weight Gain Goal
Once you’ve found your TDEE, the next step is to set your weight gain goal. Your specific goal will depend on various factors, such as your current weight, body composition, and fitness goals.
You should always consult with your doctor or a registered dietitian when setting your goal weight to ensure it’s safe and healthy.
Step Four: Calculate an Optimal Calorie Surplus
Research suggests that a safe and sustainable amount of weight gain is typically 0.25% – 0.5% of your body weight per week to minimize gains in fat mass. A hyper-energetic diet to achieve healthy weight gain should be a calorie surplus of 10% – 20%, and should contain substantial amounts of protein (1.6–2.2 g/kg/day).
How Many Calories to Gain a Pound
A general estimate is that one pound is equivalent to about 3,500 calories. While this varies from person to person, it is a good approximation to help determine a calorie surplus for weight gain.
Using this number, increasing your caloric intake by 500 calories each day could result in a weight gain of about one pound a week. We need to emphasize that this is only an estimate since there are several other factors that play a role in weight gain, but it’s a good rule of thumb to use as a starting point.
Calorie Surplus Formula
Using this information, you can calculate how many additional calories you should eat to achieve your weight gain goal. Use 10% for a moderate pace to gain weight and 20% for a more aggressive pace.
Daily Calorie Surplus = TDEE × Pace
Given a reasonable daily calorie surplus, you can calculate how long it will take to achieve your weight gain goal. Multiply your surplus by the number of days in the week (7) to find your surplus per week.
Weekly Calorie Surplus = Daily Calorie Surplus × 7
Then, divide your weekly surplus by 3,500 kcal/pound to estimate the number of pounds you’ll gain per week at this pace.
Weekly Weight Gain = Weekly Calorie Surplus ÷ 3,500 (kcal/pound)
Then, divide your total weight gain goal by the weight gain per week to estimate how many weeks it will take to reach your goal.
Total Weeks = Weight Gain Goal ÷ Weekly Weight Gain
Step Five: Monitor and Adjust
It’s important to monitor your progress and adjust your caloric intake accordingly. Monitor your weight as you progress and adjust your calorie intake if your gains are outside of the 0.25% – 0.5% range of your body weight.
If you’re not gaining weight at the desired rate, you may need to increase your calorie intake slightly. Conversely, if you’re gaining weight too quickly, you may need to adjust your calorie surplus to avoid excessive fat gain.
It’s crucial that you consume the right diet to ensure your weight gain is bulk in lean mass and not fat mass. Research suggests that for lean mass weight gain, you should adjust your diet to the following macro ratios:
You can adjust this and optimize it for your goals using our macros calculator.
It’s important to keep in mind that proper bulking does not involve overeating or eating junk food. Instead, you need to focus on eating healthy, nutrient-dense foods in a calculated way.
- Kelly, M., Resting Metabolic Rate: Best Ways to Measure It—And Raise It, Too, American Council on Exercise, https://www.acefitness.org/certifiednewsarticle/2882/resting-metabolic-rate-best-ways-to-measure-it-and-raise-it-too/
- Iraki J., Fitschen P., Espinar S., Helms E., Nutrition Recommendations for Bodybuilders in the Off-Season: A Narrative Review, Sports (Basel), 2019 Jun 26, 7(7), 154. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6680710/
- Sanford Health, How to gain healthy weight, https://news.sanfordhealth.org/healthy-living/weight-gain-performance/
- Helms E., Aragon A., Fitschen P., Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation, J Int Soc Sports Nutr, 2014 May 12, 11, 20. https://pubmed.ncbi.nlm.nih.gov/24864135/