Why use this Base64 tool?
- Encode plain text to standard Base64 or URL-safe Base64 without sending data anywhere.
- Decode Base64 back to text while tolerating whitespace and URL-safe alphabet differences.
- Choose UTF-8, ASCII, or Latin-1 so you can spot encoding mismatches early.
- Convert a local file to Base64 or a data URI and preview images immediately.
Text converter
Encode or decode text
The share URL stores settings only. Input text and output text are never placed in the link.
File converter
Convert a file to Base64
Pick a local file or drop it here. Image files can be previewed immediately from the generated data URI.
Image preview
How to use Base64 safely
Use standard Base64 when you are copying data into systems that expect the classic alphabet with +, /, and optional = padding. Use URL-safe Base64 when you need to place the result inside a query string, filename, or token format that rejects those characters.
If your task is percent-encoding for a path or query string rather than byte-to-text conversion, switch to the URL encoder / decoder tool instead of Base64.
Base64 vs. encryption
Base64 only changes binary data into text. It does not hide the contents. If the payload is sensitive, you still need proper encryption or transport security.
Why the output grows
Base64 stores each 3-byte chunk of input as 4 printable characters, so the text normally becomes about 33% larger before line breaks or data URI prefixes are added.
When file to Base64 is useful
File conversion is helpful when you need to inspect a small payload, build a data URI for a prototype, or confirm that an API field accepts the expected format. For large assets, keep in mind that Base64 adds size overhead.
Frequently asked questions
What is the difference between Base64 and Base64URL?
Standard Base64 uses + and /, while Base64URL uses - and _. Padding depends on the format that consumes the value; JWT segments use Base64URL without = padding.
Is Base64 encryption?
No. Base64 only represents bytes as text. Anyone who has the value can decode it, so use encryption and secure transport separately for sensitive data.
Why is Base64 output longer than the original?
Every 3 input bytes become 4 Base64 characters. The encoded value is therefore usually about 33% larger, with a little additional overhead when a data URL prefix is included.
Will my text or file be uploaded?
No. Text and file conversion run locally in your browser. The tool does not automatically upload the input or output.
What is the difference between forgiving and strict decoding?
Forgiving mode accepts standard or URL-safe alphabets, ignores whitespace, and restores missing padding. Strict mode checks the alphabet, padding policy, and canonical pad bits selected in the controls.
Can I use Base64URL inside a data URL?
No. A data:…;base64, value should use standard Base64. This tool automatically switches to standard Base64 with padding when you enable the data URL prefix.