Convert Text to Binary, Hex, Decimal and Back

Computers store text as bytes. This tool shows those bytes in binary, hexadecimal, decimal or octal, and turns them back into text.

It works on UTF-8 bytes, so characters outside basic ASCII, such as accented letters, symbols and emoji, are encoded correctly.

Key features

• Binary, hex, decimal and octal
• Encode and decode
• UTF-8 safe
• Choice of separator

Example

Hi  ->  01001000 01101001

How to use

1. Type your text, or paste bytes to decode.
2. Pick the format and separator.
3. Click Encode or Decode.

Use cases

• Learning how characters are stored
• Inspecting bytes of a string
• Decoding binary or hex found in logs and puzzles

In depth

Text is stored as numbers, and the encoding defines which number stands for which character. ASCII uses seven bits for 128 characters, so the letter A is 65, which is 01000001 in binary and 41 in hex. Unicode assigns a code point to every character, and UTF-8, the dominant web encoding, stores code points in one to four bytes. ASCII characters keep their single byte form, which is why plain English text looks identical in ASCII and UTF-8. Characters beyond that, such as the accented e, use two bytes beginning with the bit pattern 110.

Each representation is just another way of writing the same bytes. Eight binary digits, two hex digits, or a decimal number from 0 to 255 describe one byte, and octal needs up to three digits. Hex is the most compact and common in debugging, while binary shows individual bits. When decoding, the bytes must form valid UTF-8, otherwise characters turn into replacement symbols or decoding fails. Multi-byte characters must stay together, so cutting a byte sequence in the middle of an emoji will corrupt it. Leading zeros matter in binary groups, since they preserve the eight bit width.

Tips

• Keep a separator, such as a space, between bytes when you want readable output. Remove it only if the other system expects one continuous string, and decode with the matching setting.
• Compare hex and decimal output when debugging encoding problems. Seeing bytes such as C3 A9 for the accented e confirms the text is UTF-8, while a single E9 byte suggests Latin-1.
• Pad binary groups to eight digits when preparing data for others. A value like 1000001 without the leading zero is ambiguous when concatenated without separators.

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