Text Encoding Explained: Base64, URL Encode, and More
March 2025
For the complete 4000+ word guide with character encodings, binary, and pitfalls, see Complete Guide to Text Encoding.
Encoding converts data from one form to another so it can be stored, transmitted, or displayed safely. Different encodings solve different problems. Here is when to use each.
Base64
Base64 (RFC 4648) turns binary data into ASCII text using 64 characters (A–Z, a–z, 0–9, +, /). Use it when you need to embed binary inside text-only formats: images in HTML data URIs, file content in JSON, or binary in XML. It is not encryption; anyone can decode it. Our Base64 encode/decode tool handles this.
URL encoding (percent-encoding)
URL encoding replaces special characters with % plus two hex digits. Spaces become %20, & becomes %26. Use it when building query strings, form URLs, or passing values in links. Without it, characters like = or ? can break URLs. See our URL encoding glossary and URL encode/decode tool.
HTML entities
HTML entities escape characters that have meaning in HTML. < becomes < so it displays as text instead of starting a tag. Use it when inserting user input into HTML to prevent XSS. Our HTML entities and HTML escape tools handle this.
Binary and hex
Binary encodes text as ones and zeros; hex uses 0–9 and A–F. Both represent raw byte values. Useful for low-level debugging, teaching how computers store text, or working with protocols that expect hex. Use our text to binary and hex converter.
Which one do I need?
- Embedding an image in HTML → Base64
- Query parameter with spaces or symbols → URL encoding
- User content in HTML → HTML entities/escape
- Debugging raw bytes → Binary or hex