Weight Gain Calculator
Date
The Science of Growing (The Calorie Surplus)
Gaining weight is simple physics: Energy In > Energy Out.
If you consume more energy (calories) than your body burns, that excess energy is stored. If you are sedentary, it is stored as fat. If you are lifting heavy weights, your body uses that extra energy to synthesize new muscle tissue.
This state is called a Caloric Surplus. Without a surplus, you cannot build significant mass naturally.
The 3,500 Calorie Rule
Scientists generally accept that 1 pound of body mass equates to roughly 3,500 calories. Therefore, the math for weight gain is linear:
- +250 calorie surplus = 0.5 lbs gained per week.
- +500 calorie surplus = 1.0 lb gained per week.
- +1,000 calorie surplus = 2.0 lbs gained per week.
Clean Bulk vs. Dirty Bulk
You have a choice in how you gain weight. Speed isn't always better.
1. The Clean Bulk (Recommended)
Surplus: 250 - 500 calories.
Goal: Maximize muscle, minimize fat.
The human body has a limit on how much muscle it can build per day (about 0.25 to 0.5 lbs per week for natural lifters). Any surplus calories BEYOND that limit will inevitably become fat.
2. The Dirty Bulk
Surplus: 1,000+ calories.
Goal: Gain weight at all costs.
This involves eating everything in sight—pizza, burgers, ice cream. While the scale will go up fast, a large percentage of that weight will be body fat, which you will eventually have to diet off later.
Many skinny people claim, "I eat so much but I can't gain weight!"
Usually, this is an illusion. You might eat one huge meal, feel stuffed, and skip breakfast the next day. Tracking your calories reveals that your weekly average is still at Maintenance. Consistency > Intensity.
What Should You Eat? (Macros)
Just hitting your calorie number isn't enough. You need the building blocks.
| Macro | Role | Recommendation |
|---|---|---|
| Protein | Building Blocks | 0.8g - 1g per lb of bodyweight. |
| Carbs | Energy for Lifting | High (Fill the rest of your calories here). |
| Fats | Hormones | Moderate (0.3g - 0.5g per lb). |
Tips for Struggling to Eat Enough
If you feel nauseous trying to hit 3,000+ calories, try these hacks:
- Drink Your Calories: A smoothie with peanut butter, oats, protein powder, and milk can easily reach 800 calories and digests faster than a steak.
- Calorie Density: Choose foods that pack a punch in small volumes. Nuts, olive oil, and dried fruit are excellent.
- Frequency: Eat 5 medium meals instead of 3 huge ones to avoid bloating.