Free online tool
Base64 Encoder / Decoder
Convert between plain text and Base64 with full Unicode support — instantly, offline.
What Base64 is for
Base64 is an encoding scheme that turns arbitrary binary data — or text containing characters that would confuse a transport layer — into a safe ASCII string made of 64 well-behaved characters. It's what powers embedded images in HTML data URIs, JWT tokens, email attachments, and countless configuration files that need to smuggle binary blobs through text-only channels.
Encoding and decoding correctly
A common trap with Base64 is Unicode. The native browser btoa only handles Latin-1 characters, so encoding a string like "café" directly will throw an error. This tool wraps the browser API with a UTF-8 conversion step so emoji, accented characters, and non-Latin scripts all round-trip correctly. Everything happens locally — even sensitive tokens are safe to paste here.
+Is Base64 encryption?
No. Base64 is encoding, not encryption. Anyone with the encoded string can decode it. Never use it to hide passwords or secrets.
+Why is my Base64 result about 33% longer than the input?
Base64 uses 4 characters to represent every 3 bytes of input, so encoded output is always roughly 4/3 the size of the original.
Why use the Base64 Encoder / Decoder on ToolNest?
The Base64 Encoder / Decoder is one of more than forty free browser-based utilities we maintain on ToolNest. Every tool on the site is engineered around the same three promises: it must be fast, it must protect your privacy, and it must be genuinely useful without hiding features behind an account, a paywall, or an email capture form. Whether you use the Base64 Encoder / Decoderonce a month or several times a day, it should feel like a native part of your workflow — open the tab, get the result, move on.
Everything happens directly inside your web browser. When you type, paste, or upload something into the Base64 Encoder / Decoder, that data never leaves your device. There is no server round-trip, no logging, no analytics pixel watching your keystrokes, and no third-party API silently receiving a copy of your input. Closing the browser tab is the same as clearing your session. This is a deliberate design choice: too many free "online tools" quietly funnel user content through remote servers, and we do not think a utility as small as this one justifies that risk.
Speed is the other pillar. The Base64 Encoder / Decoder loads on a cold connection in well under a second and stays responsive on older phones, low-power laptops, and metered mobile networks. There are no heavy frameworks layered on top of the tool, no autoplay video ads, and no blocking third-party scripts. Search engines like Google reward pages that load quickly and stay interactive, but more importantly, so do human visitors who came here to get one specific job done.
If the Base64 Encoder / Decoder saves you time, the best thing you can do is bookmark this page and share it with a colleague or classmate who might need it. We also welcome direct feedback — bug reports, feature requests, and suggestions for entirely new tools all go to the same inbox and are read by a human. The best tools on ToolNest started life as a one-line reader email, and this page will keep improving as long as people keep telling us what they wish it did better.