How does UTF-8 differ from UTF-16?

In one line

The rule

UTF-8 encodes each character using 1 to 4 bytes, while UTF-16 uses 2 or 4 bytes for each character.

Let's understand it simply

Imagine you want to send a message in secret code. Each letter is turned into a number. But you have two ways to do this:

• UTF-8 is like using small boxes for common letters (like 'A', 'B', 'C'), and bigger boxes only when you need to pack special letters (like Hindi, Chinese, or emoji).
• UTF-16 uses medium-sized boxes for every letter, even if the letter is simple. For some rare letters, it uses two boxes together.

So, UTF-8 saves space for simple English, but UTF-16 is faster for languages with many special letters.

How it works

1. UTF-8:

• Each character is stored as 1, 2, 3, or 4 bytes (a byte is 8 bits).
• English letters (A-Z, a-z, numbers) use only 1 byte.
• Special letters (like 'अ', '你', '😊') use 2, 3, or 4 bytes.

1. UTF-16:

• Each character is stored as 2 bytes (16 bits) for most letters.
• Very rare characters use 4 bytes (two 2-byte units).
• Even simple English letters use 2 bytes each.

The story behind it

Both UTF-8 and UTF-16 were created to solve a big problem: computers around the world use many languages, and old systems could not handle all the letters and symbols. UTF-8 was designed by Ken Thompson and Rob Pike in 1992 to be backward compatible with old systems that used 1 byte per letter. UTF-16 was developed as part of the Unicode standard to handle all the world's writing systems in a simple way for computers.

Where you see it in real life

• Websites: Most websites use UTF-8 because it saves space for English and mixes well with other languages.
• Text files: If you open a .txt file on your phone or computer, it is usually saved in UTF-8.
• Programming languages: Many programming languages (like Python, JavaScript) use UTF-8 by default for strings.
• Windows software: Some Windows programs use UTF-16, especially for Asian languages.
• Emoji: Both UTF-8 and UTF-16 can store emoji, but the number of bytes used is different.

Why it matters

• Saves space: UTF-8 uses less memory for English, so files and websites load faster.
• Supports all languages: Both can handle Hindi, Tamil, Chinese, Arabic, emoji, and more.
• Compatibility: UTF-8 works well with older systems and the internet.
• Speed: UTF-16 can be faster for some Asian languages because it uses 2 bytes for most characters.

Common mistakes

• Thinking UTF-8 and UTF-16 are the same: They use different sizes for letters.
• Believing UTF-16 is always better: It uses more space for English text.
• Assuming all files are UTF-8: Some programs (like Notepad on Windows) may use UTF-16.

Remember it

UTF-8 is small and flexible; UTF-16 is bigger but simple for many languages.