Why does space sometimes encode as + and sometimes as %20?

Two conventions. Form-encoded (application/x-www-form-urlencoded) uses + for space (the older HTML form convention). Modern percent-encoding uses %20. URLSearchParams in browsers uses +. Always decode-with-the-same-rules-you-encoded-with.

Why does é become %C3%A9 instead of %E9?

Because the URL standard (since 2005) is UTF-8 first. é in UTF-8 is two bytes (0xC3 0xA9). Old systems used %E9 (Latin-1) — that's now non-standard.

Can I encode a URL twice safely?

Only intentionally — for example when passing an encoded URL through another URL-encoding layer (OAuth redirect chains). Each layer must decode in the reverse order. Accidental double-encoding causes %2520 instead of %20 — a common bug.

URL Encoder / Decoder

Utility

Percent-encode and decode URLs and query parameters. Supports both component and full-URI modes.

Utility

URL Encoder / Decoder

Generated on April 25, 2026

Plain textURL-encoded

Input

Output

Component mode escapes everything (incl. :/?&=#) — use for individual parameter values. Full URI mode preserves the URL syntax characters — use for entire URLs.

?What is the URL Encoder / Decoder?

The URL Encoder/Decoder converts text to and from percent-encoded form (the `%20` style of escaping you see in URLs). Two modes: 'Component' uses encodeURIComponent — escapes everything except A-Z a-z 0-9 - _ . ! ~ * ' ( ) — appropriate for individual URL parts (parameter values, path segments). 'Full URI' uses encodeURI — preserves URL syntax characters like `:/?#&=` so the URL itself stays intact. Includes a query-parameter parser that breaks decoded URLs into a key/value table.

The Formula

Percent-encoding (RFC 3986): each non-safe byte → %XX where XX is its hex value. UTF-8 multi-byte characters become multiple %XX sequences.

Practical Examples

Encode a search query for a URL: `q=hello world` → `q=hello%20world`.

Encode a path with non-ASCII: `/cafés/` → `/caf%C3%A9s/` (UTF-8 bytes for é → %C3%A9).

Decode a complex query string from analytics or a redirect: `?utm_source=google%20ads&q=cats%20%26%20dogs`.

When passing one URL inside another (OAuth redirects, share links), encode the inner URL with `encodeURIComponent`.

Frequently Asked Questions

Component (encodeURIComponent) for parameter values — encodes ALL non-safe chars including :/?#&=. Full URI (encodeURI) for entire URLs — preserves :/?#&= so the URL syntax survives. If unsure, Component is the safer default.

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URL Encoder / Decoder

URL Encoder / Decoder

?What is the URL Encoder / Decoder?

The Formula

Practical Examples

Frequently Asked Questions

When do I use Component vs Full URI?

Why does space sometimes encode as + and sometimes as %20?

Why does é become %C3%A9 instead of %E9?

Can I encode a URL twice safely?

Popular Conversions

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