Base64 Encoder / Decoder
Convert any text to Base64, or decode a Base64 string back to readable text — instantly, entirely in your browser.
Base64 Encode/Decode
Encode and decode Base64 strings online. Quickly convert text or files to Base64 and vice-versa directly in your browser.
Why Base64 Exists
Many text-based systems — HTTP headers, JSON, XML, email — can't safely carry raw binary data. Base64 re-expresses any data using just 64 safe ASCII characters, so binary content can travel through text-only channels without corruption.
Encode & Decode Both Ways
Switch instantly between converting plain text to Base64 and decoding a Base64 string back to readable text — no separate tools needed.
Nothing Leaves Your Browser
Base64 strings often contain auth credentials and API tokens. Everything here is processed locally in your browser — nothing is sent to or logged by any server.
Clear Error Messages
Pasting a malformed or truncated Base64 string shows a clear error instead of silently producing garbage — so you know the input was the problem, not the output.
Execution Use-Cases
Basic Authentication Tokens
HTTP requests frequently demand 'username:password' formats converted into Base64 hashes seamlessly attaching directly onto Authorization headers.
Image Data URIs
Embed tiny graphical vectors straight into CSS rendering pipelines bypassing external HTTP image requests entirely to boost load performance metrics.
Plain Text Payload
admin:super_secret_p@ss
Base64 Output Stream
Frequently Asked Questions
Is Base64 encryption?
No — this is the most important thing to understand about it. Base64 is an encoding, not encryption: there are no keys, and anyone with the string can decode it instantly. Never use Base64 to "hide" passwords or secrets; it only makes binary data safe to transmit as text.
Why do Base64 strings often end with an equal sign (=)?
The = is padding. Base64 processes input in 3-byte blocks that map to 4 output characters. When the input length isn't a multiple of 3, one or two = characters pad the final block so the output length stays valid.
Does Base64 make data smaller?
The opposite — Base64 output is about 33% larger than the input, because it represents every 3 bytes of data using 4 ASCII characters. Its purpose is transport safety, not compression.
What's the difference between Base64 and Base64URL?
Standard Base64 uses + and / characters, which have special meanings in URLs. Base64URL replaces them with - and _ and usually drops the = padding, making the string safe to put in a URL, filename, or JWT. If a decoder rejects a string containing - or _, it's Base64URL and needs those characters swapped back first.
Why does encoding emoji or non-English text sometimes fail?
The browser's native btoa() function only handles single-byte (Latin-1) characters, so multi-byte UTF-8 characters like emoji or non-Latin scripts throw an error unless the text is UTF-8 encoded first. Our tool handles this conversion for you.
Is there a size limit for what I can encode here?
Only your device's memory. Since everything runs in your browser, multi-megabyte strings encode and decode instantly on any modern machine.
Related Developer Logic
About This Utility
This tool is provided completely free of charge by Mavertex. Built by Kumar (an independent UI developer), our platform ensures your privacy by executing all operations strictly within your local browser DOM.
We prioritize zero-trust architecture. No files or inputs are ever uploaded to remote servers. This page serves as both an interactive web application and an educational resource explaining the mechanics of client-side operations. For further details on transparency and third-party network usage (including AdSense), please review our Privacy Policy.