BASE64 Decode and Encode

Decode from Base64 format

Simply enter your Base64 data then push the decode button.

For large Base64 strings (e.g. encoded images, documents) use the file upload form below.

Output newline separator

Decode each line separately (for multiple entries)

Remove line breaks before decoding (MIME)

Handle URL-safe encoding (Base64URL)

Decodes in real time as you type (UTF-8 only)

Decode files from Base64 format

Select a Base64 file to upload and process.

Drag & Drop Base64 file here or click to select

Output newline separator

Decode each line separately (for multiple entries)

Remove line breaks before decoding (MIME)

Handle URL-safe encoding (Base64URL)

Advanced Options

Newline Separator

Different operating systems use distinct newline characters—Unix and Windows systems, for example, do not share the same line break symbols. After decoding, any newline characters in your output will be replaced by the option you select. This setting determines how the "decode each line separately" feature behaves.

Decode Each Line Separately

With this option enabled, each line of input will be treated as a separate Base64 string and decoded independently. This is particularly useful when you need to decode multiple, distinct Base64 entries that are separated by line breaks.

Remove Line Breaks

Base64 data in MIME format (e.g. from emails) often includes line breaks every 76 characters. Enable this option to remove these line breaks before decoding. This ensures proper decoding of MIME-formatted Base64 data.

Handle URL-safe Encoding

Enable this option if your input uses URL-safe Base64 variant (RFC 4648 / Base64URL) where "-" represents "+", "_" represents "/", and padding may be omitted. This option will convert the input back to standard Base64 before decoding.

Live Mode

When Live Mode is turned on, your input is decoded instantly using your browser's built-in JavaScript functions—without transmitting any data to our servers. Please note that this mode currently supports only UTF-8 text output.

Note: For binary files (images, documents, etc.), make sure to save the output rather than copying it to prevent data corruption.

Understanding Base64 Decoding

Base64 decoding converts text-based Base64 format back into its original binary or text data. This process is essential for retrieving data that was encoded for safe transmission through text-based systems.

How Base64 Decoding Works

Base64 decoding reverses the encoding process by converting Base64 characters back into binary data. The process works with a set of 64 characters (A–Z, a–z, 0–9, and typically "+" and "/") and works by:

Validating the input Base64 string and handling any padding.
Converting each Base64 character to its 6-bit value.
Combining these 6-bit values into groups of 24 bits.
Converting these bit groups back into original bytes.
Handling any padding to recover partial final bytes.

Why Use Base64 Decoding?

Data Recovery: Retrieve original binary data from text-safe Base64 format.
Email Attachments: Extract files and images from MIME-encoded email content.
Web Resources: Convert embedded Base64 data URIs back to binary content.
API Integration: Process Base64-encoded data received from web services.

Common Applications of Base64 Decoding

Base64 decoding is essential in various scenarios including:

Email Processing: Extracting attachments from MIME-encoded messages.
Web Development: Converting Base64 data URIs back to binary resources.
API Handling: Processing Base64-encoded data from JSON or XML responses.

A Practical Example

The Base64 string TWFu when decoded becomes the word Man. The decoding process converts each Base64 character to its 6-bit value, combines these bits, and reconstructs the original ASCII characters.

Our online Base64 decoder tool provides a fast and secure way to decode your Base64 data. Whether you're extracting embedded images from web pages or processing API responses, Base64 decoding is an essential tool for modern web development.