URL Encoder and Decoder Tool

URL encoding converts text and URLs to safe, percent-encoded formats; decoding restores an encoded string to readable text. Percent-encoding protects query strings, form data, and API parameters from characters that would otherwise break a URL, and applying it consistently improves reliability across browsers, scripts, and server-side code.

Single values and large lists both process in one pass. Form mode matches application/x-www-form-urlencoded data, encoding all non-unreserved characters suits strict scenarios, and forced double-encoding produces %25HH sequences for a downstream system that expects them. Results export as CSV as well as plain text, and a character-difference view speeds up auditing a conversion.

• Reserved characters (: / ? # [ ] @ ! $ & ' ( ) * + , ; =) may need encoding depending on context.
• Unreserved characters (A-Z a-z 0-9 - . _ ~) are never encoded.
• Spaces become %20 in standard encoding or + in form mode (application/x-www-form-urlencoded).
• Encoding an already-encoded URL a second time encodes the percent signs themselves, turning %2F into %252F, which is usually not the intended result unless double-encoding is deliberately required.
• Multiple URLs in the same input are each detected and processed independently.
• UTF-8 encoding represents international characters as multiple percent-encoded bytes: café becomes caf%C3%A9.
• Encoding reserved characters that are normally left alone is available as a stricter, non-default setting for cases that require it.

Text and URLs convert to safe web formats, or percent-encoded strings restore to human-readable form, matching the behavior browsers, APIs, and forms expect.

• Encode percent-encodes text; decode converts %HH sequences back to text. Auto-detect switches between the two when the input clearly indicates the opposite action.
• Form mode replaces spaces with + for application/x-www-form-urlencoded data; leaving it off encodes spaces as %20.
• Processing each line separately converts a list line by line, which matters when handling bulk URLs or parameters rather than a single value.
• Encoding all non-unreserved characters encodes reserved symbols that are usually preserved in URLs, for contexts requiring strict encoding.
• Force double-encoding re-encodes an existing %HH sequence as %25HH, for a downstream system that expects double encoding.
• Swapping input and result feeds the output back into the input, useful for chained conversions or for confirming a round trip.
• Results export as a .txt file for a single value or a .csv file for multiple items.
• A character map and differences view shows exactly which characters changed and where, useful for a quick audit of a conversion.

Formulas and logic:

• Unreserved characters stay unchanged: A-Z a-z 0-9 - . _ ~.
• Spaces encode as %20 by default or as + in form mode.
• Each byte is written as %HH using uppercase hexadecimal during percent-encoding.
• Non-ASCII characters encode as UTF-8 bytes first, and each byte is then percent-encoded.
• Decoding optionally converts + to a space in form mode, then maps each valid %HH to its byte before UTF-8 decoding reconstructs the character.
• Force double-encoding turns an existing %HH into %25HH.
• Encoding all non-unreserved characters encodes the reserved symbols :/?#[]@!$&'()*+,;= when strict encoding is required.

Prepare, validate, and troubleshoot URLs and text for web development, SEO, analytics, and system integration.

• Build clean query strings for GET requests, encoding keys and values safely before sending requests to APIs and microservices.
• Prepare form payloads for application/x-www-form-urlencoded workflows by converting spaces to + and encoding special characters.
• Decode URLs in server logs to investigate redirects, missing pages, parameter corruption, and security filters.
• Bulk-convert lists from TXT or CSV during SEO audits, site migrations, and marketing tag cleanups.
• Handle Unicode in paths and parameters by confirming correct UTF-8 percent-encoding for internationalized content.
• Sanitize user input in scripts and low-code automations to prevent broken requests and inconsistent link handling.
• Verify webhook callback URLs and third-party redirect targets during QA, CI checks, and monitoring.
• Normalize links in analytics exports to consolidate metrics and reduce duplicate URL variants.

Encoded output reads as a sequence of %HH bytes where HH is uppercase hexadecimal. A space reads as %20, or as + in form mode. Non-ASCII characters appear as multiple %HH bytes because UTF-8 represents them with multibyte sequences. Encoding all non-unreserved characters confirms strict encoding by percent-encoding reserved symbols as well. The character map shows exactly which characters changed and where.

• Encode example: https://example.com/search?q=coffee & cream / café becomes https://example.com/search?q=coffee%20%26%20cream%20%2F%20caf%C3%A9.
• Decode example: name%3DJohn+Doe%26city%3DZ%C3%BCrich with form mode becomes name=John Doe&city=Zürich.
• Double-encode example: Force double-encode turns %2F into %252F for systems that expect a second encoding pass.

When should form mode be used? Form mode suits data submitted as application/x-www-form-urlencoded, such as classic HTML forms and many OAuth flows, because spaces become + instead of %20.
Why do some characters stay unencoded? Unreserved characters A-Z a-z 0-9 - . _ ~ do not need encoding under RFC 3986. Encoding all non-unreserved characters enforces stricter output when required.
Why do non-ASCII characters expand? UTF-8 represents them with multiple bytes, so each byte becomes a %HH sequence. This is correct and ensures cross-system compatibility.
What does double-encoding do? It converts an existing %HH to %25HH for pipelines that intentionally require a second encoding layer.