Weight Gain Calculator
Calculate how many calories you need to consume daily to gain weight at a desired rate, based on your BMR and activity level.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Weight Gain Calculator
- Enter your details: Fill in your age (years), current weight (kg), and height (cm). Select your gender and activity level from the dropdowns.
- Choose your gain rate: Pick how fast you want to gain weight: Slow (0.25 kg/week), Moderate (0.5 kg/week), or Fast (1 kg/week).
- Calculate: Click the Calculate button. The tool validates your inputs (age 1–120, weight ≥1 kg, height ≥1 cm).
- Read your results: Your daily calorie target appears, along with a breakdown: Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), and the calorie surplus needed to achieve your desired gain rate.
Note: All values must be in metric units (kg, cm). The calculator uses the Mifflin-St Jeor equation for BMR and adds ~1100 kcal per kg of weekly gain.
Previous Results
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Frequently Asked Questions
It estimates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, multiplies by an activity factor to get Total Daily Energy Expenditure (TDEE), then adds a calorie surplus based on your desired gain rate (approx 1100 kcal per kg of weight gain).
A moderate rate of 0.5 kg per week is generally considered safe and sustainable. Slower rates (0.25 kg/week) are suitable for lean gains, while faster rates (1 kg/week) may lead to more fat gain.
No, this calculator is specifically for weight gain. For weight loss, you would need a calorie deficit instead of a surplus.
