How can I check the endianness of my computer in…

In one line

Endianness tells you the order in which your computer stores bytes of data.

The rule

Endianness is the order in which bytes are arranged in computer memory for multi-byte data types (like int or float).

Little-endian: Least significant byte is stored first.
Big-endian: Most significant byte is stored first.

Let's understand it simply

Imagine you write the number 1234 on a piece of paper. In India, we write it left to right: 1, 2, 3, 4. But what if someone wrote it backwards: 4, 3, 2, 1? Computers can do something similar when storing numbers. Some computers store the smallest part first (little-endian), others store the biggest part first (big-endian).

Little-endian vs Big-endian

	Little-endian	Big-endian
Byte order for 0x01 0x02 0x03 0x04	04 03 02 01	01 02 03 04
First byte in memory	Least significant (smallest)	Most significant (biggest)

How it works

Pick a number you know in hexadecimal (for example, 0x01 0x02 0x03 0x04).
Store this number in memory using a variable (like an int).
Look at the bytes in memory, one by one.
If the first byte is 0x04, it's little-endian. If it's 0x01, it's big-endian.

Steps to check endianness in C

Store a known value in an int
Point to the first byte using a char pointer
Check the value of the first byte
Decide endianness based on the value

Where you see it in real life

C programming: Checking endianness before sending data over a network.
File formats: Some files (like images or audio) need to know endianness to read data correctly.
Networking: Data sent between different computers must agree on byte order.
Microcontrollers: Different chips use different endianness.

Why it matters

Prevents errors when sharing data between computers.
Needed when reading or writing binary files.
Important for low-level programming (like device drivers).
Some exam questions ask you to write code to check endianness.

Worked example

Here's how you check endianness in C:

unsigned int num = 1;
char *ptr = (char*)&num;
if (*ptr == 1)
    printf("Little-endian\n");
else
    printf("Big-endian\n");

Step 1: Store 1 in an unsigned int. Step 2: Point to its first byte. Step 3: If the first byte is 1, it's little-endian. Step 4: If not, it's big-endian. ```

Common mistakes

Thinking all computers use the same endianness — they do not.
Forgetting to use a pointer to check the actual bytes in memory.
Mixing up which is 'little' and which is 'big'.

Remember it

"Little-endian: Little byte comes first. Big-endian: Big byte comes first."

Check yourself

What does little-endian mean?

The smallest byte is stored first in memory.

Why do you need to check endianness before sending data over a network?

Because the receiver might use a different byte order, causing data errors.

In the C code, why do we use a char pointer to check the int's first byte?

Because a char pointer lets us look at one byte at a time.

Quick recap

Endianness is about the order of bytes in memory.
Little-endian: smallest part comes first; big-endian: biggest part comes first.
You can check endianness by looking at the first byte of a multi-byte variable.
Knowing endianness is important for data sharing and file handling.

Ask next

How do other programming languages check endianness? What happens if I ignore endianness when reading a file? Are there computers that can switch between little and big-endian?

Written by the LLOS.ai tutor. Asked by Anonymous on 23 Oct 2026, 1:01 PM IST

How can I check the endianness of my computer in a programming language?