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Calorie Surplus Calculator

Calculate the ideal calorie surplus for muscle building or healthy weight gain. This calculator shows your maintenance level and recommended surplus based on your goal, helping you gain weight in a controlled, strategic way.

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Maintenance CalBulkingTDEEAll tools
1

Enter your details

Gender
years
kg
cm

Your Calorie Surplus Plan

Example

Example figures, not your own. Worked for an active 28 year old man of 75 kg and 178 cm on a lean bulk. Enter your own details and press Calculate.

Daily Target (with surplus)

13,715kJ/day

Lean Bulk (10%): +1,247 kJ above maintenance

Maintenance Calories

12,468kJ/day

Your baseline TDEE

Expected Weekly Gain

0.3kg/week

Lean gain range

Recommended Protein Intake

150g per day

Based on 2.0 g/kg body weight - optimal for muscle protein synthesis during a bulk.

How It Works

Your maintenance calories are calculated using the Mifflin-St Jeor equation and activity factor. A surplus of 10-20% above maintenance is then added depending on your goal. A lean bulk (10% surplus, ~1,000-1,500 kJ extra) minimises fat gain, while a standard bulk (20% surplus, ~2,000-3,000 kJ extra) supports faster muscle growth.

How to use it

  1. 1Enter your gender, age, weight (kg), and height (cm)
  2. 2Select your activity level
  3. 3Choose your surplus level: lean bulk (10%) or standard bulk (20%)
  4. 4Click "Calculate" to see your daily surplus target

Quick Reference

Surplus Type% Above MaintenanceExtra kJ/dayExpected Weekly Gain
Lean Bulk10%~900 kJ~0.2 kg
Standard Bulk15%~1,350 kJ~0.3 kg
Aggressive Bulk20%~1,800 kJ~0.4 kg
Dirty Bulk30%+~2,700+ kJ~0.5+ kg

Example values based on ~9,000 kJ maintenance. A lean bulk is recommended for most people to minimise unnecessary fat gain.

How This Is Calculated

Maintenance (kcal) = BMR × Activity Factor Surplus (kcal) = Maintenance × Surplus % Target Intake = Maintenance + Surplus Expected Weekly Gain (kg) = (Surplus × 7) ÷ 7,700
Surplus %
= 10% (lean), 15% (standard), or 20% (aggressive)
7,700
= Approximate kcal per kg of body weight gain
Protein target
= 2.0 g per kg body weight for muscle building

Actual weight gain composition (muscle vs fat) depends heavily on training stimulus, sleep, protein intake, and genetics. A smaller surplus with adequate protein and progressive resistance training maximises the muscle-to-fat ratio.

Frequently Asked Questions

How big should my calorie surplus be?
For lean bulking with minimal fat gain, aim for a surplus of 10-15% above maintenance (about 1,000-1,500 kJ or 250-350 kcal per day). For faster weight gain, a 20% surplus works but will include more fat gain. Beginners can gain muscle with a smaller surplus than advanced lifters.
How much weight should I gain per week?
For lean muscle gain, aim for 0.25-0.5 kg per week. Gaining faster than this usually means you are adding more fat than muscle. Beginners may gain slightly faster in their first few months of training.
Can I build muscle without a surplus?
Beginners, people returning to training, and those with higher body fat can build some muscle at maintenance calories or even in a slight deficit (body recomposition). However, for most intermediate to advanced lifters, a calorie surplus significantly improves the rate of muscle gain.
Should I bulk or cut first?
If your body fat is above 20% (men) or 30% (women), it is generally better to cut first. Leaner individuals benefit more from bulking as they partition nutrients toward muscle more efficiently. Aim to start a bulk at 10-15% body fat for men or 18-25% for women.

Related Tools

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Calorie Maintenance CalculatorCalculate your maintenance calories - the exact number of calories you need to eat each day to maintain your current weight.Open Bulking CalculatorCalculate your calorie surplus and macro split for lean bulking. Get daily protein, carbs, and fat targets for muscle gain.Open TDEE CalculatorCalculate your Total Daily Energy Expenditure using the Mifflin-St Jeor equation. See how many calories and kilojoules you burn per day.Open