Percent-Encoding (RFC 3986) Tool

About this calculator

RFC 3986 defines the syntax of URIs and reserves a small unreserved character set — letters A–Z, a–z, digits 0–9, and the four symbols - . _ ~ — as the only characters that never need escaping. Every other byte, including spaces, reserved delimiters like ? & / #, and non-ASCII characters, must be represented as a percent sign followed by its two-digit hexadecimal byte value (e.g. a space becomes %20), so the resulting string can safely travel inside a URL without breaking its structure.

This tool applies that exact rule set to encode arbitrary text into a URL-safe form, or reverses the process to decode a percent-encoded string back to readable text. Web developers use it when building query strings or redirect URLs by hand, and API developers and QA engineers use it to debug why a request parameter isn't matching what the server expects.