Base64 Encoder & Decoder
Encode text or files to Base64, URL-safe Base64 (RFC 4648 §5), or MIME-chunked Base64.
Decode Base64 strings back to plaintext or binary. Image files are previewed directly.
All operations use the browser's native btoa() / atob() and FileReader APIs.
| Variant | Charset | Padding | Use Case |
|---|---|---|---|
| Standard (RFC 4648) | A–Z a–z 0–9 + / | = padding | Email, HTTP bodies, general encoding |
| URL-Safe (§5) | A–Z a–z 0–9 - _ | No padding | JWT tokens, URL parameters, filenames |
| MIME | A–Z a–z 0–9 + / | = padding | Email attachments, multipart bodies (76-char lines) |
Frequently Asked Questions
What is Base64 encoding?
Base64 is a binary-to-text encoding scheme using 64 printable ASCII characters. It converts binary data to a text-safe representation for emails, HTML attributes, and JSON.
Is Base64 the same as encryption?
No. Base64 is trivially reversible by anyone — no key needed. It provides zero security. For actual protection, use our AES Text Encryptor.
What is the difference between standard and URL-safe Base64?
Standard Base64 uses + and / which conflict with URLs. URL-safe Base64 replaces them with - and _, making output safe for URL parameters. JWT tokens use URL-safe Base64.
Why is the Base64 output longer than the input?
Base64 encodes every 3 bytes as 4 characters, resulting in approximately 33% size overhead.