Base64
Encode and decode Base64 for text, images, files, and HTTP Basic Auth headers.
Text Base64
Encode and decode text to/from Base64. Supports standard and Base64URL variants with auto-detection.
About Base64
Base64 is a free, browser-based tool that encodes and decodes text, images, files, and HTTP Basic Auth headers to and from Base64. All processing happens in your browser, so your data never leaves your device.
It covers four modes in one page: Text, Image, File, and Basic Auth. Text mode handles both standard Base64 and the URL-safe Base64URL variant, with auto-detection so you do not have to choose a direction manually.
Use it to read an encoded data URI, embed an image as a string for HTML or CSS, inspect or build an Authorization: Basic header, or turn a file back into a downloadable copy. Image and file modes detect the MIME type from the data and can preview or download the result.
Files are limited to 10MB and everything runs client-side using your browser's built-in encoding, so nothing is uploaded to a server. Because Base64 is an encoding, not encryption, it offers no security: credentials in a Basic Auth header are trivially reversible by anyone.
Frequently asked questions
- Is Base64 encryption?
- No. Base64 is a reversible encoding used to represent binary data as text, not a way to secure it. Anyone can decode it, so never treat a Base64 string, including a Basic Auth header, as a secret.
- What is the difference between standard Base64 and Base64URL?
- Base64URL replaces the + and / characters with - and _ and drops the trailing = padding, making it safe to use in URLs and filenames. The text mode supports both and can auto-detect which one you pasted.
- Is my data uploaded anywhere?
- No. All encoding and decoding runs locally in your browser, and no input is sent to any server. Files are processed in memory up to a 10MB limit.