Free Base64 Encoder & Decoder Online
Encode UTF-8 text to Base64 or decode Base64 back to text. Real-time, browser-only, full Unicode support.
Base64 is a binary-to-text encoding that represents data using only 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). Used to embed binary data in JSON, email (MIME), URLs, and other text-only contexts. Notepad AI's encoder/decoder supports full UTF-8, runs in your browser, and never uploads your data.
Common Use Cases
Data URI images in CSS / HTML
Embed small images inline (data:image/png;base64,...) to skip an HTTP request.
API tokens & keys in URLs
Safely pass binary tokens through URL query strings without breaking on special characters.
Email attachments (MIME)
Email protocols only handle ASCII — attachments must be Base64-encoded for transport.
JWT inspection
Decode the payload portion of JSON Web Tokens to inspect their contents during debugging.
Base64 Tool Comparison (2026)
Notepad AI vs popular Base64 encoder/decoder tools. Updated 2026.
| Tool | No Upload | UTF-8 / Emoji Safe | No Ads | Encode + Decode | Paired with Editor |
|---|---|---|---|---|---|
| Notepad AI Base64 | ✅ | ✅ TextEncoder/Decoder | ✅ | ✅ | ✅ |
| base64decode.org | ⚠️ Live mode local, file uploads sent | Limited | ❌ Ads | ✅ | ❌ |
| freeformatter.com | ❌ Server-processed | Limited | ❌ Ads | ✅ | ❌ |
| base64.sh | ✅ | ✅ | ✅ | ✅ | ❌ |
| 64baser.com | Unknown | Limited | ❌ Ads | ✅ | ❌ |
| Jam.dev Base64 | ✅ | ✅ | ✅ | ✅ | ❌ |
Comparison last verified 2026-05-18. The unique angle: full UTF-8 (emoji, Chinese, Cyrillic) safety + pairing with a full notepad.
Related Tools
Base64 Encoder/Decoder FAQ
What is Base64?
Base64 is a binary-to-text encoding that represents binary data using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It's widely used to embed binary data (images, files, encryption keys) in text-only contexts like JSON, email (MIME), URLs, or HTTP headers.
Is the encoder free?
Yes — completely free, no signup, no login, no limits on text length.
Does it handle Unicode and emoji?
Yes. The encoder uses TextEncoder/TextDecoder for proper UTF-8 handling, so non-ASCII characters (emoji, Chinese, Cyrillic, etc.) encode and decode correctly.
Is my data private?
Yes. All encoding and decoding happens in your browser using built-in atob/btoa APIs. Nothing is uploaded, logged, or transmitted to any server.
What happens if I paste invalid Base64?
The decoder returns an error message ('Invalid Base64 input') if the input isn't well-formed Base64. Common issues: extra spaces, invalid characters, or missing padding (=).
Why is Base64 longer than the original text?
Base64 encodes every 3 bytes of input as 4 characters of output — a ~33% size increase. This is the cost of using only 6 bits per character (vs 8 bits in raw binary). Worth it when you need to embed binary in text-only formats.
Is Base64 a form of encryption?
No. Base64 is encoding, not encryption — anyone can decode it without a key. Don't use Base64 to 'hide' sensitive data. It's only useful for safe transport through text-only channels.
When should I use Base64?
Common use cases: embedding small images in CSS/HTML data URIs, encoding binary attachments in email (MIME), passing tokens/keys in URLs, fitting binary data into JSON, and avoiding line-break issues in HTTP headers or auth tokens.