Base64 / URL Encode-Decode
Encode or decode UTF-8 text as Base64, Base64URL, a URL component or a full URL. Inspect invalid input errors without confusing encoding with encryption.
Keep the value intact in transit.
IN YOUR BROWSER / PRIVATE INPUTHow to use the
Base64 / URL Encode-Decode
- 01
Choose the representation
Base64, Base64URL and URL percent-encoding solve different transport problems. Select the one required by the receiving format.
- 02
Choose encode or decode
Paste the complete text. Standard Base64 decoding expects valid padding; Base64URL accepts its URL-safe alphabet and optional padding.
- 03
Review the exact output
Check Unicode text, spaces and reserved URL characters before copying or downloading. Decoding binary bytes as text requires valid UTF-8.
The alphabets are not interchangeable
| Choice | Behavior | Typical use |
|---|---|---|
| Base64 | Standard alphabet with +, / and padding | Textual representation of bytes. |
| Base64URL | URL-safe - and _; generated without padding | Formats such as JWT sections. |
| URL component | Escapes reserved separators inside one value | A query parameter value or path segment. |
| Full URL | Preserves URL structural separators | Encoding a complete URL string without treating it as one component. |
Encode a query value rather than a whole query by accident
The component and full-URL operations follow encodeURIComponent/decodeURIComponent and encodeURI/decodeURI respectively. They are not a full URL parser or campaign-link builder. A plus sign is not automatically treated as a space because form-url-encoding is a separate convention.
URL component input:
coffee & designcoffee%20%26%20designBase64 operates on bytes; this tool makes UTF-8 explicit
Encoding converts the input text to UTF-8 bytes before producing Base64. This avoids the common failure of passing non-Latin text directly to a byte-only browser encoder. Decoding reverses the bytes and uses a strict UTF-8 decoder.
Not every Base64 value represents readable text. Images, archives and arbitrary binary data can decode to bytes that are not valid UTF-8; this text utility reports that limit rather than displaying replacement characters as if conversion succeeded. Use the dedicated image/Base64 tool for supported image data.
Avoid representation mistakes
Do not treat encoding as secrecy
Anyone with the encoded value can generally reverse it. Base64 is not encryption or authentication.
Match the receiving convention
Base64URL, standard Base64 and HTML form query strings have different rules. Confirm the required format.
Decode once deliberately
Repeated percent-decoding can change the meaning of nested encoded separators. Work from the expected layer rather than repeatedly clicking until something looks readable.
Base64 / URL Encode-Decode:
questions, answered.
Does Base64 encrypt a password or token?
No. Base64 is reversible encoding and does not provide secrecy, integrity or authentication.
Why does decoding a Base64 image fail as text?
Image bytes are generally not valid UTF-8 text. Use the Image to Base64 / Base64 to Image tool for supported image payloads.
Why is a plus sign not decoded into a space?
This utility uses URI decoding, not application/x-www-form-urlencoded parsing. That form convention treats plus specially.
What is different about Base64URL?
It uses - and _ instead of + and /, and this tool omits generated padding. The underlying bytes are still an encoding, not encrypted content.
The calculations and checks above describe this tool's implementation. Use these primary references for the underlying formats and publishing guidance.
Base encodings, RFC 4648 ↗ (opens in a new tab)URL component encoding ↗ (opens in a new tab)Keep the value intact in transit.
Use the controls above, inspect the actual result and keep the source until you are ready to use your new copy.
Use the Base64 / URL Encode-Decode↑