What is the difference between encodeURIComponent and encodeURI in JavaScript?

encodeURIComponent encodes ALL special characters (including "/", "?", "&", "=", "#", "+"), making it suitable for individual query parameter values. encodeURI preserves URL protocol and path delimiters (such as "https://", "/", "?", and "#") while encoding spaces and non-ASCII Unicode characters, making it suitable for full URL strings.

How does Percent-Encoding convert multi-byte Unicode characters (like Emojis or Arabic)?

Under RFC 3986, non-ASCII characters are first converted into their UTF-8 byte sequences (1 to 4 bytes). Each byte is then formatted as a percent sign "%" followed by two hexadecimal digits. For example, the Rocket emoji 🚀 (4 UTF-8 bytes: 0xF0 0x9F 0x9A 0x80) is encoded as %F0%9F%9A%80.

Why do forms replace spaces with "+" instead of "%20"?

The legacy HTML form encoding standard (application/x-www-form-urlencoded) specifies that space characters should be encoded as "+" rather than "%20". Our tool provides dedicated support for both standards.

Tools/URL Encoder

Unicode URL Percent-Encoder & Query Studio

Percent-encode strings for safe URL inclusion and query strings, or decode percent-encoded URLs back into human-readable Unicode text under RFC 3986.

22Percent Entities (%XX)

136 BUTF-8 Byte Size

4Query Parameters Detected

componentActive Encoder Mode

Encoding Algorithm / Standard:

Quick Presets:

Font Size (16px):

Raw String / URL (To Encode)Live Input Buffer

https://www.example.com/search?q=Unicode 16.0 & Symbols 🚀&category=web-dev&price=€99.99

Percent-Encoded Output

https%3A%2F%2Fwww.example.com%2Fsearch%3Fq%3DUnicode%2016.0%20%26%20Symbols%20%F0%9F%9A%80%26category%3Dweb-dev%26price%3D%E2%82%AC99.99

Parsed URL Query Parameters (4 Key-Value Pairs)

Parameter Key	Decoded Parameter Value
q	Unicode 16.0
Symbols 🚀
category	web-dev
price	€99.99

URL Percent-Encoding (RFC 3986) Ready to Run

Using standard urllib.parse in Python.

1import urllib.parse

3query = "Unicode 16.0 ⚡ & Urdu: سلام"

5# RFC 3986 percent-encode

6encoded = urllib.parse.quote(query, safe='')

7print("Encoded:", encoded)

9# Decode back

10decoded = urllib.parse.unquote(encoded)

11print("Decoded:", decoded)

Python 3Zero external runtime dependencies • Standard Library

UTF-8 & Unicode 16.0 Compatible

The Networking Architecture of RFC 3986 Percent-Encoding

The Uniform Resource Identifier (URI) specification was standardized under RFC 3986. By design, valid URI components are strictly restricted to a small subset of 7-bit US-ASCII characters. Any character outside this reserved and unreserved range must be percent-encoded:

1. Unreserved Characters (Never Encoded):Uppercase & lowercase letters (A-Z, a-z), digits (0-9), and four safe symbols: hyphen -, underscore _, dot ., and tilde ~.

2. Reserved Characters (Context-Dependent):Delimiters like :, /, ?, #, [, ], @, !, $, &, ', (, ), *, +, ,, ;, =.

How Multi-Byte UTF-8 Characters are Percent-Encoded

When international scripts (like Arabic, Urdu, Devanagari, or Emojis) are included in a URL, they are first converted into their UTF-8 binary bytes:

• English Letter ‘A’ (1 Byte 0x41): A (Unchanged)

• Space (1 Byte 0x20): %20 (or + in forms)

• Accented Letter ‘é’ (2 Bytes 0xC3 0xA9): %C3%A9

• Rocket Emoji 🚀 (4 Bytes 0xF0 0x9F 0x9A 0x80): %F0%9F%9A%80

Frequently Asked Questions (FAQs)

How do I decode double-encoded URLs (e.g. %2520)?+

Paste your string into the input and select "Decode". If the string was double-encoded, decode it twice to revert %2520 to %20 and then to a normal space.

Why should I use encodeURIComponent for query parameters?+

If a query parameter value contains characters like "&" or "=", not encoding them will cause the web server to misinterpret them as delimiters separating new parameters.

Is this URL encoding safe for private API keys and tokens?+

Yes! All encoding and decoding operations run 100% locally in your web browser without sending your URLs across the network.