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URL Encode Decode | Percent-Encode or Decode Text for URLs

Encode and decode URLs and query strings with RFC 3986 percent-encoding, showing each unsafe character converted. Essential for developers building links, API calls and forms with special characters.

Last updated: June 2026 · Free · No sign-up required

Results

Enter values above and click Calculate to see your result instantly.

Quick reference

Character	Encoded
space	%20
?	%3F
&	%26
=	%3D
/	%2F
é	%C3%A9

edit_note What you need

Have your numbers ready before you start. The form above shows the exact fields required, with units and example values for each. Any blank or out-of-range field is flagged before the result is computed so you never get a misleading answer.

function How it computes

The URL encoder decoder applies the published reference formula and rounds the result to a useful precision. The methodology section below explains each step so you can verify the math.

verified Trusted source

Reference values and constants come from an authoritative source. Every quarter we re-check the source and update the calculator if the published guidance changes. The link is visible in the methodology section so you can verify it yourself.

tips_and_updates Read it like this

Read the headline number first, then open the breakdown card to see how each input contributed. If a result looks off, the breakdown almost always shows which value drove it. Adjust that input and recalculate — the answer updates instantly.

Interpretation guide

Situation	Action
Value going into a query string	Encode it
%xx soup from logs/analytics	Decode it
Full URL with structure	Encode only the components, not the separators

lightbulb Worked example

Let's say you are using the URL Encode / Decode. Encodes or decodes text for safe use in URLs. Paste any string with spaces, special characters, or Unicode, and the tool converts it to percent-encoded form per RFC 3986, or reverses an encoded Enter the values that match your situation into the input fields and press calculate — using realistic numbers makes the result directly useful for you.

Result: The calculator instantly applies the formula Encode: unsafe byte → %HH (UTF-8, RFC 3986); decode reverses %HH sequences and returns the result with appropriate precision.

What this means: Read the result in the context of what you are measuring. The step-by-step breakdown lets you confirm the math and understand which input most affects the outcome.

Formula & methodology

Formula: Encode: unsafe byte → %HH (UTF-8, RFC 3986); decode reverses %HH sequences

The URL Encode / Decode is built on a well-established calculation method. It uses the formula Encode: unsafe byte → %HH (UTF-8, RFC 3986); decode reverses %HH sequences to turn your inputs into a reliable result. Encodes or decodes text for safe use in URLs. Paste any string with spaces, special characters, or Unicode, and the tool converts it to percent-encoded form per RFC 3986, or reverses an encoded string back to readable The steps are shown on the page so you can follow the reasoning from input to output.

Choose encode or decode and paste your text.
Encoding converts every reserved/unsafe character to its UTF-8 percent form (encodeURIComponent semantics); decoding reverses it.

Worked example — live-verified: "hello world?key=value&x=1" → hello%20world%3Fkey%3Dvalue%26x%3D1; decoding returns the original exactly.

Authoritative source: MDN Web Docs

Frequently asked questions

What is URL encoding?

The URL Encode / Decode is free, private, and accurate: it runs entirely in your browser (no uploads, no accounts), applies the standard calculation, and explains each step so you can verify the result. Encodes or decodes text for safe use in URLs. Paste any string with spaces, special characters, or Unicode, and the tool converts it to percent-encoded form per RFC 3986, or reverses an encoded string back to readable text. Perfect for developers preparing There is no limit on usage, and it works on any device.

When do I need to encode?

Encode whenever a URL contains characters outside the safe set — spaces, &, ?, #, %, Unicode, and symbols — whether building a query string, a link parameter, or an API request. Leaving them raw breaks parsing: an unencoded & starts a new parameter and an unencoded # truncates the URL. Encode user-generated input before putting it in any URL.

Whats the difference between %20 and + for spaces?

Both represent a space, but they belong to different standards: %20 is the RFC 3986 percent-encoding used in URL paths and generally safe everywhere, while + is the application/x-www-form-urlencoded convention used in query strings and HTML form data. Some servers decode + as a space in queries but not in paths. Use %20 for maximum compatibility; the tool outputs %20 and decodes both.

Should I encode a whole URL at once?

No — encode only the components that need it (the path segments and query values), never the scheme, host, or existing delimiters like ? and =. Encoding the whole URL would turn the ? and / into %3F and %2F, breaking the URL entirely. The tool is designed for pasting the portion to encode; encode values separately and assemble the URL with the delimiters intact.

How does Unicode encode?

Enter the required values into the input fields and press the calculate button. The tool applies the formula Encode: unsafe byte → %HH (UTF-8, RFC 3986); decode reverses %HH sequences and returns the result with a short explanation of each step, so you can check the working yourself.

What does the URL Encode / Decode do?

Encodes or decodes text for safe use in URLs. Paste any string with spaces, special characters, or Unicode, and the tool converts it to percent-encoded form per RFC 3986, or reverses an encoded string back to readable text. Perfect for developers preparing. The calculator takes your inputs, applies the standard calculation, and returns a clear result so you can make an informed decision without doing the math by hand.

What formula does the URL Encode / Decode use?

Encoding converts every unsafe byte to percent notation: Encode: unsafe byte → %HH (UTF-8, RFC 3986), and decoding reverses each %HH sequence back to the character. Paste any string with spaces, symbols, or Unicode and the tool produces the URL-safe form — for example, a space becomes %20 and an & becomes %26 — so links work correctly across browsers and APIs.

Is the URL Encode / Decode free and private?

Yes — the URL Encode / Decode. There is no sign-up, no paywall, no trial, and no limit on how many calculations you can run. CalcaTools covers its costs with non-intrusive display advertising, so the calculator itself never asks for payment or restricts any feature.

How accurate is the URL Encode / Decode?

The URL Encode / Decode applies the standard formula: Encode: unsafe byte → %HH (UTF-8, RFC 3986); decode reverses %HH sequences. It is tested against published worked examples before launch and uses native double-precision arithmetic, so results are accurate to typical precision for the values you enter — with no intermediate rounding that could distort the answer.

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