Calorie Surplus Calculator - How Much to Eat to Build Muscle

Same TDEE, three different surpluses - and only one builds mostly muscle

A calorie surplus is the difference between what you burn (TDEE) and what you eat. The calculator uses the Mifflin-St Jeor equation to estimate your BMR, multiplies it by an activity factor, then adds 10%, 15% or 20% depending on your chosen bulk type. The result is a daily calorie target, a full macro breakdown (protein at 1.8 g/kg, fat at 1.0 g/kg, remaining calories from carbs) and a week-by-week weight projection until you reach your goal.

How to use the Calorie Surplus Calculator - step by step

Current weight (kg) - your weight this morning, after using the bathroom, before eating. Use a digital scale for accuracy.
Target weight (kg) - the weight you want to reach. A realistic first bulk target is +5 to +10 kg.
Height (cm) - your height without shoes. Used in the BMR formula.
Age (years) - BMR decreases with age, so your surplus adjusts accordingly.
Sex - male or female. The Mifflin-St Jeor formula uses different constants for each.
Activity level - how often and how intensely you exercise. This multiplier converts BMR into TDEE.
Bulk type - lean (+10%), standard (+15%) or aggressive (+20%). Lean builds more muscle relative to fat, aggressive is faster but adds more fat.
Read your results - daily calories, macro split (protein/fat/carbs in grams), weekly weight projection and estimated timeline.

Lean Bulk vs Standard vs Aggressive - comparison

Not every bulk is the same. A larger surplus means faster weight gain - but a bigger share of that weight is fat.

Bulk type	Surplus	Pace	Muscle vs fat	Best for
Lean Bulk	+10% TDEE	~0.25 kg/wk	70/30	Advanced lifters, physique-focused
Standard Bulk	+15% TDEE	~0.35 kg/wk	60/40	Most trainees
Aggressive Bulk	+20% TDEE	~0.5 kg/wk	50/50	Beginners, hardgainers, underweight

Calorie targets for different profiles

Your surplus calories depend on TDEE, which depends on body weight, height, age, sex and activity level.

Profile	TDEE	Lean (+10%)	Standard (+15%)	Aggressive (+20%)
Male, 70 kg, active	2,700	2,970	3,105	3,240
Male, 85 kg, very active	3,280	3,608	3,772	3,936
Female, 55 kg, active	2,050	2,255	2,358	2,460
Female, 65 kg, moderate	2,200	2,420	2,530	2,640

Practical examples

Example 1: Male, 70 kg to 80 kg, 178 cm, 24 years old, very active, lean bulk
TDEE: 2,855 kcal - +10%: 3,141 kcal/day. Pace: 0.25 kg/wk. Timeline: 40 weeks (~9 months)

Example 2: Male, 65 kg to 75 kg, 175 cm, 20 years old, moderately active, standard bulk
TDEE: 2,508 kcal - +15%: 2,884 kcal/day. Pace: 0.35 kg/wk. Timeline: 29 weeks (~7 months)

Example 3: Female, 52 kg to 58 kg, 163 cm, 22 years old, active, standard bulk
TDEE: 2,010 kcal - +15%: 2,312 kcal/day. Pace: 0.35 kg/wk. Timeline: 17 weeks (~4 months)

Example 4: Male, 60 kg to 70 kg (hardgainer), 180 cm, 18 years old, very active, aggressive bulk
TDEE: 2,716 kcal - +20%: 3,259 kcal/day. Pace: 0.5 kg/wk. Timeline: 20 weeks (~5 months)

Example 5: Male, 85 kg to 90 kg (advanced), 185 cm, 30 years old, very active, lean bulk
TDEE: 3,220 kcal - +10%: 3,542 kcal/day. Pace: 0.25 kg/wk. Timeline: 20 weeks (~5 months). Advanced trainees build muscle slower.

FAQ - Frequently asked questions

How many extra calories should I eat to build muscle?

The optimal surplus is 10-20% above TDEE, typically 250-500 kcal per day. A lean bulk (+250 kcal) minimizes fat gain. An aggressive bulk (+500 kcal) produces faster scale weight, but a larger share is fat you will need to cut later.

Can I build muscle without a surplus?

Yes, but slowly. Body recomposition (eating at maintenance while training hard) works for beginners, detrained lifters and people with higher body fat. After 6-12 months of consistent training, a surplus becomes necessary for continued progress.

How much protein do I need for bulking?

1.6-2.2 g per kg of body weight. This calculator uses 1.8 g/kg - the sweet spot supported by meta-analyses. At 80 kg that is 144 g of protein per day. Good sources: chicken breast, eggs, cottage cheese, tofu, whey protein.

Is dirty bulking worth it?

Not recommended. Dirty bulking (eating everything with no calorie control, +30-50% TDEE) packs on weight fast, but most of it is fat. You then need a long, hard cut to strip it off. Lean or standard bulking delivers better long-term results - less fat to lose means a shorter cutting phase.

How long should a bulk last?

Typically 3-6 months, followed by 1-2 months of maintenance or a mini-cut (mild deficit for 4-6 weeks). Bulking longer than 6 months without a break raises body fat percentage, worsening calorie partitioning. Optimal cycle: 4 months bulk, 6 weeks mini-cut, repeat.

How much muscle can I build per month?

Realistically: beginners 0.5-1 kg/month, intermediates 0.25-0.5 kg/month, advanced 0.1-0.25 kg/month (McDonald model). The rest of your weight gain is water, glycogen and some fat. That is why lean bulking works - it limits the fat portion.

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