What is URL-safe Base64?

It replaces "+" and "/" with "-" and "_" and may omit the final padding characters. This form is commonly used in JWTs and URLs.

Can I decode to a file?

Yes. Decoded binary can be downloaded with an appropriate file extension you choose.

Does encoding increase size?

Base64 expands binary size by roughly 33% due to 4-character encoding of 3 bytes.

Base64 Encoder and Decoder

Encode and decode text and small files to Base64 or Base64URL. Inspect byte length and copy results for data URLs or APIs.

Files and content are processed locally in your browser and are not uploaded to our server.

About this tool

Convert UTF-8 text or small files to Base64, or decode Base64 into readable text or a downloadable file. Choose a URL-compatible form when preparing content for JWTs or URLs.

How to use

Encode and decode text or small files
URL-compatible Base64 form
Display output size and final padding information
Copy decoded text or download the decoded file
Choose mode: Select encode or decode and text vs file input.
Provide input: Paste a string or pick a file under the recommended size.
Copy output: Grab Base64 text or save decoded binary locally.

Examples

Create a data URL for a small image or SVG file
Read Base64 content received from an API
Create a URL-compatible value for a query parameter
Store a small text setting in an encoded form

Limitations

Large files may exceed browser memory—keep under ~5 MB
Decoding invalid Base64 shows a clear error
The entered text or selected file is processed directly in your browser and is not sent to a server.

FAQ

What is URL-safe Base64?: It replaces "+" and "/" with "-" and "_" and may omit the final padding characters. This form is commonly used in JWTs and URLs.
Can I decode to a file?: Yes. Decoded binary can be downloaded with an appropriate file extension you choose.
Does encoding increase size?: Base64 expands binary size by roughly 33% due to 4-character encoding of 3 bytes.