Base64 Encode & Decode
Encode text to Base64 or decode Base64 back to plain text. Supports URL-safe Base64 (RFC 4648). Converts as you type. No upload, no server — runs entirely in your browser.
How to Use
What is Base64?
Base64 is an encoding method that converts binary data into a set of 64 printable ASCII characters. The name comes from representing data using 64 symbols: A-Z, a-z, 0-9, and the characters + and /. Every 3 bytes of input becomes 4 Base64 characters, making the output about 33% larger than the original.
Common uses: HTTP Basic Authentication headers encode "username:password" in Base64. JWT tokens use Base64 URL-safe encoding for their header and payload sections. Data URIs embed images directly in HTML or CSS. Email systems use Base64 to encode attachments.
Worked Example
Frequently Asked Questions
What is Base64 encoding?
Base64 is an encoding scheme that converts binary data into a text string using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It is used to safely transmit binary data through channels that only support text, such as email, HTTP headers, and JSON payloads.
Why use Base64 instead of plain text?
Base64 allows binary data — images, files, certificates — to be embedded in text-based formats. Common use cases include embedding images as data URIs in HTML/CSS, encoding credentials in HTTP Basic Auth headers, storing binary data in JSON, and encoding JWT token sections.
What is URL-safe Base64?
URL-safe Base64 replaces the + character with - and / with _ to produce a string safe for use in URLs and filenames without percent-encoding. It is specified in RFC 4648 and is used in JWT tokens, OAuth tokens, and any URL parameter where standard Base64's + and / characters would be misinterpreted.
How do I decode a Base64 string?
Switch to Decode mode using the toggle at the top. Paste your Base64 string in the input box. The decoded text appears in the output box automatically. The tool handles both standard Base64 (with + and /) and URL-safe Base64 (with - and _).
Does Base64 encrypt data?
No. Base64 is encoding, not encryption. Anyone can decode a Base64 string instantly without any key. Never use Base64 to protect sensitive data. For security, use proper encryption algorithms. Base64 only changes the format of data — it adds no secrecy.