How Many Calories Should a Skinny Beginner Eat to Gain Muscle?

If you’re a skinny beginner trying to gain muscle, one of the most important things to understand is how many calories you should eat each day.

Many beginners train hard but still struggle to gain weight because they simply don’t eat enough calories amongst other reasons. Your body needs extra energy to build new muscle tissue, and without a calorie surplus, muscle growth becomes very difficult.

The good news is that gaining weight doesn’t require complicated diets or strict meal plans. Once you know your maintenance calories and add a small calorie surplus, muscle gain becomes much easier.

In this guide, you’ll learn:

 

• • How to estimate your maintenance calories

• • How many extra calories to add for muscle gain

• • How fast you should gain weight

• • How to track your calories properly

Step 1: Estimate Your Maintenance Calories

Your maintenance calories are the number of calories your body needs to maintain its current weight.

A simple way to estimate this is by multiplying your body weight by an activity factor.

Here are some common estimates:

Low activity (little exercise)
Bodyweight × 30

Moderate activity (training 3–4 times per week)
Bodyweight × 33

Very active (training 5–6 times per week)
Bodyweight × 35

For example:

If you weigh 60 kg and train around 4 times per week:

60 × 33 = about 1980 calories per day

So your maintenance calories would be roughly 2000 calories per day.

If you want a more detailed estimate that includes factors like height, age, and activity level, you can use a calculator such as this one:

https://www.calculator.net/calorie-calculator.html

Tools like this use established nutrition formulas to estimate your daily calorie needs. Remember that these numbers are only starting points, and you should adjust them based on how your weight changes over time.

Step 2: Add a Calorie Surplus

Once you know your maintenance calories, the next step is adding extra calories so your body has enough energy to build muscle.

This is called a calorie surplus.

Lean Bulk

A lean bulk usually involves adding about 300–400 calories above maintenance.

Example:

Maintenance calories = 2000
Lean bulk target = 2300–2400 calories per day

This approach leads to slower but cleaner muscle gain with less fat accumulation.

Aggressive Bulk

An aggressive bulk adds around 500–700 calories above maintenance.

Example:

Maintenance calories = 2000
Aggressive bulk target = 2500–2700 calories per day

This can lead to faster weight gain but may also increase body fat more quickly.

For most beginners, a moderate surplus of about 300–400 calories is a good starting point.

How Fast Should You Gain Weight?

Muscle growth takes time, even for beginners.

A realistic rate of weight gain during a muscle-building phase is:

0.25–0.5 kg per week

If your weight increases slower than this, you may not be eating enough calories.

If your weight increases much faster than this, you may be gaining unnecessary body fat.

The best way to monitor progress is to weigh yourself multiple times per week and track the weekly average.

If your weight stays the same for 2–3 weeks, increase your calorie intake by about 150–200 calories per day.

Strength Progress Is a Good Sign

Weight gain alone does not guarantee muscle growth. A strong indicator that your calorie intake is working is strength progress in the gym.

Small increases in strength over time usually indicate that your body is building muscle. This could be in the form of one extra rep than last time, adding more weights, more sets, moving on to harder variation(if doing body weight exercises).

If your body weight is stays same but strength increases then it’s a good sign that you’re building muscle and burning fat at the same time.

How to Track Your Calories

Tracking your calories helps ensure that you are actually eating enough to support muscle growth.

Many beginners believe they are eating a lot, but when they start tracking their food, they realize their calorie intake is still too low.

There are several simple ways to track your calories.

Using apps

Apps like MyFitnessPal or Cronometer allow you to log foods and automatically calculate your daily calories.

You simply enter what you eat, and the app estimates your calorie intake for the day.

Using ChatGPT

Another simple method is to log your meals and ask ChatGPT to estimate the calories.

For example:

Breakfast
3 eggs
2 slices of bread
1 glass of milk

Lunch
150 g rice
100 g chicken
vegetables

Dinner
rice and lentils

ChatGPT can estimate the approximate calories for each meal and give you a daily total.

This works well if you keep your meals relatively consistent.

Tracking manually

Some people prefer a simple approach: writing their meals and calorie estimates in a notebook or notes app.

This works as long as you stay consistent and track your food regularly.

To make calorie tracking more accurate, it’s helpful to measure your food portions using a kitchen scale.

In a separate guide, I explain how to weigh food properly for calorie tracking.

Final Thoughts

If you’re a skinny beginner trying to gain muscle, the most important factor is maintaining a consistent calorie surplus.

Start by estimating your maintenance calories, add about 300–400 extra calories, and aim to gain around 0.25–0.5 kg per week while gradually getting stronger in the gym.

Tracking your calories and body weight will help you adjust your intake over time and stay on the right path toward building muscle.

Gaining muscle is a long and slow process, as long as you’re eating in surplus and achieving progressive overload, you’re on the right track.