Have you ever submitted a search form with Japanese text and watched the URL fill with something like %E6%97%A5%E6%9C%AC? Or tried to share a link containing Japanese characters, only to have it break or garble in chat and email? If you work with websites or apps, this is a familiar frustration.
In this guide, we explain how URL encoding (percent-encoding) works in plain terms. You will learn which characters can appear in a URL as-is, how to encode Japanese text, spaces and symbols, how to build query parameters, and how to decode percent-encoded strings back to readable text.
What is URL encoding?
URL encoding (percent-encoding) replaces characters that cannot be used directly in a URL with a “%” followed by two hex digits. For example, the Japanese character あ becomes %E3%81%82, and a space becomes %20.
Some characters cannot go into a URL directly:
| Character type | Examples | Treatment |
|---|---|---|
| Latin letters and digits | A-Z, a-z, 0-9 | Used as-is |
| Reserved characters | - _ . ~ | Used as-is |
| Japanese text | あ, 日, 本 | Must be encoded |
| Space | (blank) | Becomes %20 |
| Some symbols | ! ’ ( ) * etc. | May be encoded |
The “E3 81 82” in %E3%81%82 is the byte sequence of the character in UTF-8, written in hex. In other words, URL encoding converts a character into bytes and rewrites them in a URL-safe form.
Why it matters: putting Japanese text or symbols into a URL directly can cause browsers and servers to interpret the link differently, breaking it or making search results behave incorrectly. Encoding keeps the URL identical everywhere.
Common encoding examples
Here are the encoded forms of a few common characters:
| Original | Encoded | Notes |
|---|---|---|
| あ | %E3%81%82 | Japanese (UTF-8) |
| 日 | %E6%97%A5 | Japanese (UTF-8) |
| space | %20 | one blank |
| ! | %21 | encoded under RFC 3986 |
| ’ (apostrophe) | %27 | encoded under RFC 3986 |
| ( ) | %28 %29 | parentheses |
For example, the “日本語” part of “https://example.com/search?q=日本語” is encoded as:
https://example.com/search?q=%E6%97%A5%E6%9C%AC%E8%AA%9EYou can see that 日 = %E6%97%A5, 本 = %E6%9C%AC and 語 = %E8%AA%9E are simply joined together.
How to read it: the two hex digits after each % (00-FF) represent one byte. A Japanese character is usually 3 bytes in UTF-8 (あ = E3 81 82), which is why you see three % groups per character.
Using Japanese in query parameters
Query parameters (the part of a URL after “?”) often need to carry Japanese text. The steps are simple:
- Decide the parameter name and value (e.g. q=日本語)
- Encode the value (日本語 → %E6%97%A5%E6%9C%AC%E8%AA%9E)
- Assemble the URL (https://example.com/search?q=%E6%97%A5%E6%9C%AC%E8%AA%9E)
Browsers often display the Japanese text as-is in the address bar, but when you share a link or embed it in code, the encoded form is safer. This also prevents garbled text when sharing URLs in email, chat or social media.
How to decode
Turning an encoded string back into readable text is called decoding. “%E6%97%A5%E6%9C%AC” decodes to “日本”. Decoding is useful when you want to make sense of percent-encoded output in logs or tools.
Heads up: spaces can be represented in two ways. URL encoding uses "%20", while form submissions (application/x-www-form-urlencoded) often use "+". Some tools treat "+" as a space and others do not, so check if your decoded result looks off.
How to use the Tools Hub URL encoder / decoder
Encoding by hand gets error-prone as Japanese text and symbols pile up. The Tools Hub URL encoder / decoder transforms pasted text with a single click, and everything runs in your browser — your text is never sent to a server.
How to use it (three steps)
Paste your text
Paste the Japanese text or the percent-encoded string you want to transform into the input area.
Pick a conversion
Press "Encode" or "Decode". Encoding is fully RFC 3986 compliant, so symbols like ! and parentheses are converted correctly too.
Copy and use the result
Press "Copy" to put the result on your clipboard and use it directly in links or code.
The tool from this guide
URL Encoder / Decoder
Free, no sign-up required, and your text never leaves your browser.
Summary
- URL encoding replaces unsafe characters with “%” plus two hex digits; Japanese, spaces and some symbols are affected
- A Japanese character is usually 3 bytes in UTF-8, producing three % groups (あ = %E3%81%82)
- Spaces become “%20”; the “+” form is specific to form submissions
- To include Japanese in a query parameter, encode the value before assembling the URL
- Decoding turns percent-encoded strings back into readable text
- The Tools Hub tool provides fully RFC 3986-compliant encoding
URL encoding looks intimidating at first — all those “%” signs — but two rules cover most cases: Japanese text becomes three %-groups per character, and spaces become %20. When you need to check a conversion, the tool has you covered.
FAQ
What is URL encoding?
URL encoding (percent-encoding) replaces characters that cannot be used directly in a URL — such as Japanese text, spaces and some symbols — with “%” followed by two hex digits.
How is Japanese text encoded?
Japanese characters are converted to their UTF-8 byte sequences and written as percent notation such as %E3%81%82. One character typically produces three % groups (three bytes).
Is a space “%20” or “+”?
In URL encoding, a space is “%20”. The “+” form is a separate convention used by form submissions (application/x-www-form-urlencoded). Tools and environments differ, so check your result.
How do I decode an encoded string?
Paste the percent-encoded string into the Tools Hub URL encoder / decoder and press “Decode”. The original Japanese text is restored instantly.
