Convert anything to Base64 and back
Convert text and files to and from Base64. Handy for email attachments, data URIs and API payloads where only text is allowed.
Text or file
Base64
Private by design
Your text and files are processed on your device and never uploaded.
Optional password lock
AES-256-GCM with a PBKDF2 key. Locked output opens only in this tool.
Text, files, URL-safe
Drop in any file up to 64 MB, or switch to URL-safe Base64.
How to take advantage of the Base64 encoder decoder app
Follow these steps to convert text or files in about a minute, with or without a password lock.
Choose Encode or Decode
Use the switch at the top of the tool. Encode turns text or a file into Base64, and Decode turns Base64 back into the original.
Add your input
Type or paste text, or press Upload file, or drop a file onto the input card. Any file up to 64 MB works.
Set your options
Turn on Lock with password to protect the result, or URL-safe for Base64 that fits in links and tokens. To decode locked data, enter the same password.
Run the conversion
Press Encode or Decode, or use Ctrl+Enter (⌘+Enter on a Mac). The status line tells you what happened.
Copy, download or go the other way
Copy the result, download it as a file, or press Use as input to run it back through the opposite mode and check your work.
Why use a Base64 encoder decoder
Base64 solves one problem well: moving data through places that only understand text. Here is where it helps, and why this tool is a safe way to do it.
Send files through text-only channels
Email bodies, JSON, XML and form fields can’t carry raw bytes. Base64 turns any file into plain characters that pass through unchanged.
Embed images and fonts directly
Data URIs let you inline a small image, icon or font in HTML or CSS, which saves an extra network request.
Work with APIs and tokens
Many APIs expect Base64 for payloads, credentials and keys. URL-safe mode keeps the output clean in links, headers and file names.
Inspect and debug in seconds
Decode a string to see what is inside it, from an authorization header to an encoded setting, without writing a script.
Keep your data private
Everything runs in your browser and nothing is uploaded, so confidential text and files stay on your device.
Add protection when you need it
Base64 alone is not encryption. The optional password lock encrypts your data with AES-256-GCM before it is encoded.
Frequently asked questions
Quick answers about how the tool works, your privacy and the password lock.
What is Base64?
Base64 is a way of writing any data, including files and images, using only 64 printable characters: A–Z, a–z, 0–9, plus (+) and slash (/). That lets binary data travel safely through places that only accept text, such as email, JSON, HTML and URLs.
Is Base64 a form of encryption?
No. Base64 only changes how data is written, and anyone can decode it instantly. If the content is private, turn on the password lock when you encode it.
Are my text and files uploaded anywhere?
No. Encoding, decoding and encryption all happen inside your browser, so your text and files never leave your device.
How does the password lock work?
Your password is turned into a key with PBKDF2 (SHA-256, 210,000 rounds) and a random salt, and your data is then encrypted with AES-256-GCM. To decode, you must type the same password. If you forget it, the data cannot be recovered, so keep it somewhere safe.
Can I open locked output in another tool?
No. Locked output uses this tool’s own format, so it only opens here. Output without a password lock is standard Base64 and works anywhere.
What is URL-safe Base64?
It swaps + and / for - and _ and drops the trailing = padding, so the result can sit safely in URLs, file names and tokens. The decoder understands both the standard and URL-safe forms.
How big can a file be, and how large is the output?
Any file type up to 64 MB works. Base64 output is about 33% larger than the original, because every 3 bytes become 4 characters.
What can the decoder read, and what if the result is a file?
It accepts data URIs (the data:…;base64, prefix) as well as text with spaces or line breaks. If the decoded bytes are not readable text, they are treated as a file and offered as a download, with the type detected for PNG, JPG, GIF, WebP, PDF and ZIP.