Base64 is a binary-to-text encoding scheme that represents binary data using only 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It is used to transmit binary data over channels that only support text, such as email, JSON APIs, and HTML data URIs.

Does encoding make data smaller?

No. Base64 encoding increases data size by approximately 33%. Every 3 bytes of input become 4 characters of output. Base64 is for compatibility, not compression.

code Dev Tool

Base64 Encoder / Decoder

Encode text to Base64, decode Base64 strings back to text, or convert an image file to a Base64 data URI — all instantly in your browser. Zero data sent to any server.

Input Text

Base64 Output

Base64 Input

error_outline Invalid Base64 input

Decoded Text

Drop an image here, or click to browse

Supports PNG, JPEG, GIF, WebP, SVG, and more

What Is Base64?

Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters: A–Z, a–z, 0–9, +, and /, with = for padding. It was designed to safely transmit binary content — like images or binary files — through systems that only support text, such as email (SMTP), JSON APIs, and HTML.

Common Use Cases

Inline Images

Embed images directly in HTML or CSS using a data:image/png;base64,… URI. Useful for small icons that shouldn't require an extra HTTP request.

API Payloads

Send binary data (images, PDFs, audio) in JSON requests without special content encoding. Many REST APIs accept Base64-encoded file attachments.

Auth Headers

HTTP Basic Authentication encodes credentials as Base64(username:password) in the Authorization header.

JWT Tokens

JSON Web Tokens use Base64URL (a URL-safe variant) to encode their header and payload segments.

Frequently Asked Questions

What is Base64?

Base64 is a binary-to-text encoding scheme that represents binary data using only 64 printable ASCII characters. It is used to safely transmit binary data (like images or files) over text-only channels like email, JSON APIs, and HTML attributes.

Does encoding make files smaller?

No. Base64 increases size by approximately 33% — every 3 bytes of binary data become 4 ASCII characters. Base64 is designed for compatibility, not compression. If you need smaller files, use gzip or similar compression before or after encoding.

Is Base64 the same as encryption?

No. Base64 is encoding, not encryption. Anyone can decode a Base64 string back to its original content without any key or password. Do not use Base64 to protect sensitive data — use proper encryption like AES-256.

Is my data sent to a server?

No. All encoding and decoding happens instantly in your browser using JavaScript's built-in btoa() and atob() functions. Your text and files never leave your device.