OmniCalcsURL Encoder / Decoder
Percent-encode special characters for safe URLs, or decode encoded strings back to readable text.
How to Use This Converter
Choose encode or decode, paste the text and convert. The query-string option encodes spaces and slashes too — ideal for parameters.
- Use encodeURIComponent when passing values inside query strings.
- Decoding is automatic and safe to apply to any URL string.
Frequently Asked Questions
Why do spaces become %20?
Spaces aren't allowed in URLs, so they're encoded as %20 (the hex value of the space character). The plus sign is an older alternative.
EncodeURIComponent vs encodeURI?
encodeURIComponent escapes nearly everything (good for parameter values); encodeURI preserves reserved characters like / and ? (good for whole URLs).
Is percent-encoding reversible?
Yes — decoding maps every %XX back to its original character, and this tool handles multi-byte UTF-8 correctly.
What about UTF-8 characters?
Non-ASCII characters are encoded as their UTF-8 byte sequences, each byte shown as %XX.
Practical Example
With "Encode for query string" checked, encode a b&c and the output is a%20b%26c — the space becomes %20 and the ampersand becomes %26.
- Decoding
a%20b%26creturnsa b&c, proving the round trip is exact. - Non-ASCII text is encoded per UTF-8, so
cafébecomescaf%C3%A9. - With the query-string option off, reserved characters like
/and?stay unencoded (encodeURI behavior).
What Your Results Mean
- Percent-encoding — each unsafe character is replaced by
%followed by its two hex digits, such as%20for a space. - Query-string mode — encodes nearly every reserved character, ideal for parameter values.
- UTF-8 bytes — one or more
%XXgroups represent the multi-byte encoding of a single non-ASCII character.