Calorie Calculator to Gain Weight
Calculate exactly how many calories you need to gain weight. Get your personalised TDEE, daily calorie target, calorie surplus, and macro breakdown based on your body stats and activity level.
Weight Gain Calorie Calculator
Mifflin-St Jeor equation · TDEE + Calorie Surplus
Used to apply the correct Mifflin-St Jeor BMR formula.
Enter your age in years. Calculator is intended for adults aged 15 and over.
Be honest — overestimating activity is the most common mistake when calculating TDEE.
Or enter a custom surplus below. A surplus of 250–500 kcal/day is recommended for most people.
Adjust manually if you want a precise target. Changing this will override the surplus level buttons above.
Higher protein supports muscle protein synthesis. At least 1.6g/kg is recommended when training.
Your Calorie Target
Daily calories to gain weight at your chosen rate
Enter your stats and click Calculate My Calorie Target to see your personalised daily calories, TDEE, and macro breakdown.
Activity Multipliers & Expected Gains
How your activity level affects your TDEE, and what to expect at different calorie surplus levels. Based on average TDEE of 2,400 kcal/day for a moderately active adult male.
| Activity Level | Multiplier | Example TDEE | +300 kcal Target | Est. Weekly Gain |
|---|---|---|---|---|
| Sedentary (desk job, no exercise) | × 1.2 | 1,920 kcal | 2,220 kcal | ~0.25 kg/week |
| Lightly Active (1–3 days/week) | × 1.375 | 2,200 kcal | 2,500 kcal | ~0.25 kg/week |
| Moderately Active (3–5 days/week) | × 1.55 | 2,480 kcal | 2,780 kcal | ~0.25 kg/week |
| Very Active (6–7 days/week) | × 1.725 | 2,760 kcal | 3,060 kcal | ~0.25 kg/week |
| Extremely Active (athlete/labourer) | × 1.9 | 3,040 kcal | 3,340 kcal | ~0.25 kg/week |
| Surplus Type | Daily Surplus | Est. Weekly Gain | Est. Monthly Gain | Best For |
|---|---|---|---|---|
| Lean Bulk | +150 kcal | ~0.12 kg | ~0.5 kg | Minimising fat, recomposition |
| Steady Bulk | +300 kcal | ~0.25 kg | ~1.0 kg | Most people — best balance |
| Moderate Bulk | +500 kcal | ~0.42 kg | ~1.7 kg | Faster gains, some fat accepted |
| Aggressive Bulk | +750 kcal | ~0.62 kg | ~2.5 kg | Underweight individuals, hardgainers |
| Very Aggressive | +1,000 kcal | ~0.83 kg | ~3.3 kg | Not recommended — significant fat gain |
Calorie Calculator FAQ
Everything you need to know about calculating calories to gain weight, building muscle, and getting your macros right.
To gain weight, you need to consume more calories than your body burns each day. This is called a calorie surplus. A moderate surplus of 250 to 500 calories per day above your Total Daily Energy Expenditure (TDEE) is recommended for steady, lean weight gain of approximately 0.25 to 0.5 kg per week. A larger surplus of 500 to 1,000 calories per day will result in faster weight gain of around 0.5 to 1 kg per week, but may include more fat gain.
TDEE stands for Total Daily Energy Expenditure. It is the total number of calories your body burns in a day, accounting for your Basal Metabolic Rate (BMR) and your physical activity level. BMR is calculated using the Mifflin-St Jeor equation, which factors in your age, sex, height, and weight. This figure is then multiplied by an activity multiplier ranging from 1.2 for sedentary individuals to 1.9 for extremely active people.
A clean bulk involves eating a modest calorie surplus (typically 250 to 500 calories above TDEE) from nutritious, whole foods to maximise muscle gain while minimising fat accumulation. A dirty bulk involves eating a large calorie surplus with less regard for food quality, leading to faster total weight gain but a higher proportion of body fat. A clean bulk is generally recommended for most people seeking to improve body composition.
For weight gain, particularly muscle mass, a common macro split is: Protein at 25–35% of calories (around 1.6 to 2.2g per kg of bodyweight), Carbohydrates at 40–50% of calories to fuel workouts and recovery, and Fat at 20–30% of calories for hormonal health. Protein is the most important macro for muscle building. Aim for at least 1.6g of protein per kg of bodyweight per day when training.
A realistic and healthy rate of weight gain is 0.25 to 0.5 kg per week for most people. Beginners to resistance training may gain muscle faster, while advanced trainees gain muscle more slowly. Gaining weight faster than 0.5 kg per week often means a significant portion of the gain is body fat rather than muscle. Consistency over months and years matters more than the speed of any individual week.
While it is possible to gain weight through diet alone, resistance training (weight lifting) is strongly recommended if you want to gain lean muscle mass rather than primarily fat. Without training, a calorie surplus will result in weight gain that is mostly fat tissue. Combining a calorie surplus with progressive resistance training maximises muscle protein synthesis and leads to a healthier, more muscular physique.
Online calorie calculators provide a scientifically grounded estimate using validated equations like Mifflin-St Jeor, but individual metabolism varies. Use the result as a starting point, track your weight over 2 to 4 weeks, and adjust your intake by 100 to 200 calories if you are not seeing the expected rate of gain. Real-world adjustments based on your body’s response are always more accurate than any formula.
The best foods for healthy weight gain are calorie-dense, nutrient-rich options including: lean meats such as chicken, beef, and salmon; dairy products like whole milk, Greek yoghurt, and cheese; eggs; nuts and nut butters; avocados; whole grains such as oats, rice, and wholegrain bread; legumes; and starchy vegetables. Liquid calories from whole milk and smoothies can help if you struggle to eat enough volume.