Base64 encoding and decoding: a practical guide
What Base64 is, when to use it, and how to encode or decode text and files safely in your browser.
3 min read · Updated June 8, 2026
Try it now: Base64 Encoder
Open toolWhat is Base64?
Base64 represents binary data using 64 printable ASCII characters. It's how you embed an image in a CSS file, send a small file inside JSON, or put binary data into a URL or email — anywhere a transport only safely handles text.
When to use it (and when not to)
Use Base64 for small assets and data that must ride through text-only channels. Avoid it for large files: Base64 inflates size by roughly 33%, so a 9 MB file becomes ~12 MB.
Encode and decode instantly
The Base64 Encoder and Decoder run in your browser, so even sensitive strings stay on your device. Paste text to encode, or paste Base64 to decode it back to the original.