Convert Unicode to Bytes

UTF-8 is variable-length: ASCII (codepoints 0-127) = 1 byte each, Latin Extended / Greek / Cyrillic = 2 bytes, most CJK and other BMP characters = 3 bytes, supplementary planes (emoji, rare ideographs) = 4 bytes. So “Hello” is 5 bytes, but “Héllo” is 6 (the é is 2 bytes), and “🌍 Hello” is 11 bytes (4 for emoji + 1 space + 5 for ASCII).

Same bytes, different presentations. Hex (base 16) is the most compact 2-char-per-byte format – universal in debugging tools and hex editors. Decimal (base 10) is easier for humans to read but takes 3 chars per byte. Binary (base 2) shows raw bits – best for teaching how UTF-8 encodes characters (lead byte patterns, continuation bytes), but verbose at 8 chars per byte.

Both indicate hex but in different contexts. 0x is the C/JavaScript/Python/Rust prefix for hex numeric literals: int x = 0x48;. x is the C/Python prefix for hex escapes inside string literals: "x48x65x6C". Use x with no separator to get a paste-able string literal: x48x65x6Cx6Cx6F = “Hello” in C/Python.

By scanning the first byte token: binary if it’s 8 characters of 0s and 1s, decimal if it’s all digits and short (≤3), hex if it contains A-F or is exactly 2 characters. Prefixes (0x, x, 0b) are stripped before detection. Mixed-format input is not supported – each conversion treats the entire input as one format.

It marks continuation bytes of a multi-byte UTF-8 character. The first byte gets the actual character glyph; subsequent bytes (in 2-4 byte sequences) get ↳ to visually show they’re part of the same character. Useful for understanding how an emoji like 😀 maps to 4 specific bytes: the first row shows “😀” and the next three show “↳”.

Because not all prefixes apply to all formats. 0x only prefixes hex. x only prefixes hex (it’s an escape syntax). 0b only prefixes binary. If you select x with decimal format, the prefix is silently skipped because there’s no x escape for decimal in any programming language. The dropdown could be smarter about hiding incompatible options, but cross-checking gives you flexibility.

200,000 characters. The per-byte grid caps at 256 displayed rows (since emoji-heavy text expands quickly – 50 emoji is already 200 bytes), but the conversion processes the full input. Copy and Download give you the complete output.

That sibling tool focuses on hex output specifically with a per-character grid. This tool offers three byte representations (hex/decimal/binary) and a per-byte grid (one row per byte, not per character). Use the sibling for clean hex output, use this when you need decimal or binary, or when you want to see exactly how bytes line up with their source characters.

No. All UTF-8 encoding, byte formatting, and decoding run in your browser using TextEncoder and TextDecoder. Open DevTools → Network and confirm zero requests fire – even when you Convert or Download. Safe for tokens, credentials, or any sensitive text.

Yes. Total bundle is about 18 KB. Load once, disconnect, keep using. Pure JavaScript using browser standard library – no remote dependencies. Useful for debugging encoding issues on airgapped systems or in offline environments.