What is URL encoding (percent-encoding)?

URLs only allow a limited set of characters. Everything else — spaces, accents, &, ?, #, emoji — must be written as a % followed by the character’s UTF-8 bytes in hex. A space becomes %20, é becomes %C3%A9. That’s percent-encoding, defined in RFC 3986.

When should I choose “value” mode vs “whole URL” mode?

Use value mode (encodeURIComponent) for a single piece of data going into a URL — a search query, a redirect target, any query-string value. It encodes every reserved character. Use whole-URL mode (encodeURI) only when you have a complete URL and want to keep its structure — it leaves :, /, ?, & and = untouched.

Why did my + turn into a space — or not?

In the query part of URLs submitted by old-style HTML forms, spaces are encoded as +. Modern percent-encoding uses %20 instead, and a literal + means plus. If you’re decoding a query string and see + where spaces should be, enable the “treat + as space” option.

Why do I get an error when decoding?

A % in the input must always be followed by exactly two hex digits. If your text contains a bare % (say, “50% off”) or was cut mid-sequence (%C3 without the next part), strict decoding fails. Find the stray % and either fix the sequence or encode the % itself as %25.

What’s the difference between URL encoding and Base64?

Both make data text-safe, but for different targets: percent-encoding makes text safe inside URLs and keeps it mostly readable; Base64 re-writes any data in a 64-character alphabet and is unreadable. Query parameters want percent-encoding; binary payloads and tokens usually use Base64.

Does double encoding cause problems?

Yes — it’s one of the most common URL bugs. Encoding twice turns %20 into %2520, because the % itself gets encoded. The fix: encode exactly once, at the moment you build the URL. If you receive text that looks like %25XX everywhere, decode it twice to recover it.

Is my text sent anywhere?

No — encoding and decoding run entirely in your browser using the standard built-in functions. Nothing is uploaded or logged, and the tool works offline once the page has loaded. URLs often contain tokens and personal data, so local processing is the right default.

URL Encoder / Decoder

Percent-encode text for URLs or decode %20-style strings — component or full-URL mode, in your browser.

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Direction

What are you encoding?

Encodes every reserved character — use for query-string values.

Text or URL to encode

URL encode and decode — the right way, in your browser

Every developer eventually ships a broken link because a space, ampersand or accent slipped into a URL unencoded. This free URL encoder / decoder converts text to properpercent-encoding (%20-style, per RFC 3986) and back — instantly, as you type, with full UTF-8 support so accents, Hindi, Chinese and emoji all encode correctly.

Two modes, because there are two jobs

The classic mistake is using one encoding function for everything. Value mode(encodeURIComponent) is for data going into a URL — it encodes &, =, ? and / so your search term can’t break the query string. Whole-URL mode (encodeURI) is for a complete address — it encodes spaces and accents but keeps the structural characters intact. The tool makes the choice explicit and explains it, so you stop guessing.

Decoding messy real-world strings

Query strings copied from logs and analytics exports come with their own quirks — most famously+ meaning space in form-submitted queries. There’s a switch for exactly that. And when decoding fails, the tool tells you why in plain language: a stray % that isn’t followed by two hex digits, usually from truncated or double-encoded input.

Private by design

URLs routinely carry session tokens, email addresses and tracking parameters. Everything here runslocally in your browser — no upload, no server logs, works offline once loaded.

More free developer tools

Building link slugs rather than query strings? Use the URL slug generator. Encoding binary data or credentials? That’s a job forBase64. And if your decoded query contains JSON, paste it into the JSON formatter to make it readable.

Frequently Asked Questions

What is URL encoding (percent-encoding)?
URLs only allow a limited set of characters. Everything else — spaces, accents, &, ?, #, emoji — must be written as a % followed by the character’s UTF-8 bytes in hex. A space becomes %20, é becomes %C3%A9. That’s percent-encoding, defined in RFC 3986.
When should I choose “value” mode vs “whole URL” mode?
Use value mode (encodeURIComponent) for a single piece of data going into a URL — a search query, a redirect target, any query-string value. It encodes every reserved character. Use whole-URL mode (encodeURI) only when you have a complete URL and want to keep its structure — it leaves :, /, ?, & and = untouched.
Why did my + turn into a space — or not?
In the query part of URLs submitted by old-style HTML forms, spaces are encoded as +. Modern percent-encoding uses %20 instead, and a literal + means plus. If you’re decoding a query string and see + where spaces should be, enable the “treat + as space” option.
Why do I get an error when decoding?
A % in the input must always be followed by exactly two hex digits. If your text contains a bare % (say, “50% off”) or was cut mid-sequence (%C3 without the next part), strict decoding fails. Find the stray % and either fix the sequence or encode the % itself as %25.
What’s the difference between URL encoding and Base64?
Both make data text-safe, but for different targets: percent-encoding makes text safe inside URLs and keeps it mostly readable; Base64 re-writes any data in a 64-character alphabet and is unreadable. Query parameters want percent-encoding; binary payloads and tokens usually use Base64.
Does double encoding cause problems?
Yes — it’s one of the most common URL bugs. Encoding twice turns %20 into %2520, because the % itself gets encoded. The fix: encode exactly once, at the moment you build the URL. If you receive text that looks like %25XX everywhere, decode it twice to recover it.
Is my text sent anywhere?
No — encoding and decoding run entirely in your browser using the standard built-in functions. Nothing is uploaded or logged, and the tool works offline once the page has loaded. URLs often contain tokens and personal data, so local processing is the right default.