What Is the Weight Gain Calorie Calculator?
This calculator estimates how many calories you should eat per day to gain weight at a target rate. It combines your maintenance calories (TDEE) with a daily calorie surplus based on how fast you want to gain. It is a general-purpose nutrition tool and is not specific to any country.
How to Use It
Enter your gender, weight (kg), height (cm), age, and activity level. Then set your desired weekly weight gain in pounds. The calculator first finds your Basal Metabolic Rate (BMR), multiplies it by your activity factor to get your Total Daily Energy Expenditure (TDEE), and adds the surplus needed to reach your goal.
The Formula Explained
We use the Mifflin-St Jeor equation for BMR. For men: \(\text{BMR} = 10\cdot\text{weight} + 6.25\cdot\text{height} - 5\cdot\text{age} + 5\). For women: \(\text{BMR} = 10\cdot\text{weight} + 6.25\cdot\text{height} - 5\cdot\text{age} - 151\). \(\text{TDEE} = \text{BMR} \times \text{activity factor}\). Since roughly 3,500 calories equal one pound of body mass, the daily surplus:
$$\text{surplus} = \frac{\text{desired\_gain\_lb\_per\_week} \times 3500}{7}$$Daily intake = TDEE + surplus.
Worked Example
A sedentary (1.2) woman weighing 60 kg, 165 cm tall, age 30, wanting 1 lb/week:
$$\text{BMR} = 10\cdot60 + 6.25\cdot165 - 5\cdot30 - 151 = 600 + 1031.25 - 150 - 151 = 1330.25$$$$\text{TDEE} = 1330.25 \times 1.2 = 1596.3$$$$\text{Surplus} = 1 \times \frac{3500}{7} = 500$$$$\text{Daily intake} = 1596.3 + 500 = 2096.3 \text{ calories/day}$$
FAQ
Why pounds and not kilograms for the gain? The 3,500 calories-per-pound rule is the most widely cited estimate, so we keep the goal in pounds for accuracy.
Is 1 lb/week safe? A gain of 0.25–1 lb/week is a common, manageable target for lean mass gains. Faster rates increase fat gain.
Are these numbers exact? No. They are estimates. Track your weight weekly and adjust intake up or down by 100–200 calories as needed.
