URL Encoder Decoder — Encode and Decode URLs and Query Strings

URLs have a limited set of characters they can contain without encoding. Spaces, ampersands, equals signs, and most other punctuation need to be percent-encoded before they're valid in a URL. You've seen this in action: a Google search for "hello world" appears in the address bar as ?q=hello+world or ?q=hello%20world. The CalcHub URL Encoder Decoder handles both directions and explains what's happening.

How Percent Encoding Works

Characters that aren't "URL-safe" are replaced by a % followed by their hex value:

Character	Encoded	Reason
Space	%20 (or +)	Not allowed in URLs
&	%26	Used as query parameter separator
=	%3D	Used as key=value separator
#	%23	Used as fragment identifier
?	%3F	Starts query string
/	%2F	Path separator
@	%40	Used in userinfo
+	%2B	When literal + needed (vs space)
"	%22	Not URL-safe
<	%3C	Not URL-safe
>	%3E	Not URL-safe

Safe characters (never encoded): A–Z, a–z, 0–9, -, _, ., ~

How to Use It

Encoding:

1. Open CalcHub and go to URL Encoder.
2. Choose what you're encoding:

- Full URL: Encodes only the query parameter values, preserving /, ?, &, = structure - URL component: Encodes everything including /, ?, & (for embedding a URL inside another) - Query string value: Encodes just a single parameter value

1. Paste text and copy encoded output.

Decoding:

1. Switch to Decode mode.
2. Paste the encoded URL or text.
3. Readable text appears immediately.

Full URL vs. Component Encoding

This is the most common source of confusion:

Input	Full URL encode	Component encode
https://example.com/search?q=hello world	https://example.com/search?q=hello%20world	https%3A%2F%2Fexample.com%2Fsearch%3Fq%3Dhello%20world

Use full URL encoding when the URL will be used as-is in a browser. Use component encoding when the entire URL is being embedded as a value inside another URL (e.g., a redirect parameter).

Common Real-World Uses

• Building query strings: Encoding user input before appending to a URL
• Debugging redirects: Decoding percent-encoded URLs in logs or error messages
• API work: Encoding parameters in API requests
• Email links: Mailto links with subject/body need URL encoding
• SEO analysis: Reading encoded URLs in analytics reports

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What's the difference between %20 and + for spaces?

Both represent a space, but in different contexts. %20 works everywhere; + for spaces is valid only in query strings (the application/x-www-form-urlencoded format). When in doubt, use %20 — it's always safe.

Why does %2F (/) cause problems in some paths?

Some web servers and frameworks treat %2F in the path as a literal slash, while others treat it as an encoded slash distinct from the path separator. Django, for example, blocks %2F in paths by default. If you're encoding a path segment that shouldn't be interpreted as a directory separator, check your framework's behavior.

Can I decode a URL that's been double-encoded?

Yes. Double-encoding happens when a URL is encoded twice: a space becomes %20, then the % itself gets encoded to %2520, resulting in %2520 in the string. The decoder has a "decode once" and "decode all layers" mode to handle this.

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