---
title: 5.6 Array Size
description: "The size of an array can be calculated using the `sizeof` operator. It returns the total size of the array in bytes, including the storage occupied by all its elements. ``` #include int main(void) { int numbers[] = {10, 20,…"
url: "https://edcret.in/docs/c-programming/arrays/5-6-array-size/"
updated: "2026-10-27"
category: C Programming / Arrays
---

# 5.6 Array Size

The size of an array can be calculated using the `sizeof` operator. It returns the total size of the array in bytes, including the storage occupied by all its elements.

```
#include <stdio.h>

int main(void)
{
    int numbers[] = {10, 20, 30, 40, 50};

    size_t total_size = sizeof(numbers);
    size_t element_size = sizeof(numbers[0]);
    size_t element_count = total_size / element_size;

    printf("Array size: %zu bytesn", total_size);
    printf("Element size: %zu bytesn", element_size);
    printf("Number of elements: %zun", element_count);

    return 0;
}
```

### Example Output

On an implementation where `sizeof(int)` is 4 bytes:

```
Array size: 20 bytes
Element size: 4 bytes
Number of elements: 5
```

### Explanation

The expression:

```
sizeof(numbers)
```

returns the total size of the array in bytes.

The expression:

```
sizeof(numbers[0])
```

returns the size of one array element.

Dividing the total array size by the size of one element calculates the number of elements:

```
sizeof(numbers) / sizeof(numbers[0])
```

This calculation works when `numbers` is an actual array object, rather than a pointer to an element.

### Array Size Expressions

| Expression | Purpose |
| --- | --- |
| `sizeof(numbers)` | Total array size in bytes |
| `sizeof(numbers[0])` | Size of one element in bytes |
| `sizeof(numbers) / sizeof(numbers[0])` | Number of elements in the array |

The `sizeof` operator returns a value of type `size_t`, which should be printed using `%zu`.

**Important:** When an array is passed to a function as a parameter, it is adjusted to a pointer parameter. Inside that function, `sizeof` returns the size of the pointer, not the size of the original array. The array length must be passed separately when needed.