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Base64 Converter

Base64 Converter is a free online tool to quickly encode or decode text and files in Base64 format. It’s useful for developers who need to transform data to Base64 (for embedding binary data in text form) or decode Base64 back to original form. All processing is done in your browser for speed and privacy.

Convert text and files to and from Base64 encoding with support for multiple character encodings.

Input

Output

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What is Base64 encoding and why use it?

Base64 encoding is a way to represent binary data (like images or files) in text form using only 64 ASCII characters. It’s commonly used to embed images in HTML/CSS, include attachments in emails (MIME), or store binary data in JSON. Developers use Base64 to ensure data remains intact when transmitted over text-only systems.

Please refer to our more comprehensive Base64 Explained Guide to learn more in-depth!

Base64 Converter Tool Features:

  • Automatic Base64 detection:
    • Checking if the string length is valid (multiple of 4)
    • Verifying it only contains valid base64 characters
    • Attempting to decode and re-encode to confirm validity
  • Multiple Encoding Support:
    • UTF-8, ASCII, ISO-8859-1, UCS-2
  • File Upload support:
    • Supports reading text files
    • Automatically processes file contents
  • Copy to Clipboard:
    • Copy button that appears when there’s a result
    • Shows feedback when copied
    • Disables when there’s no content to copy
  • Download as file:
    • Download encoded/decoded content as file.
    • For binary content, if mime type is detected, automatically applies proper extensions to file name(e.g .png, .pdf etc)
  • Binary Content:
    • Encode/Decode binary files/content.
  • URL Parameter Support:
    • Pre-load data directly from links (external site integration, through “data” query parameter)
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How do I use this Base64 Converter tool?

Basic Text Conversion

  1. Enter or paste your text in the input textarea
  2. Choose your preferred mode:
    • Auto Detect: Automatically determines if the input is Base64 encoded
    • Encode: Force Base64 encoding of the input
    • Decode: Force Base64 decoding of the input
  3. Select your character encoding:
    • UTF-8 (default, recommended for most uses)
    • ASCII
    • ISO-8859-1
    • UCS-2
  4. View the result below the input area
    • Click “Copy Result” to copy the converted text to the clipboard
    • Or click “Download” to download as file.

Encode/Decode File Content

  1. Click “Upload File” to select a text file
  2. The file content upload status will be shown in the input area with converted data on the output area.
  3. Conversion happens automatically based on your selected mode and encoding

URL Parameter Integration

The tool supports external linking, allowing you to create URLs that automatically load data into the converter.

Creating Shareable Links

You can create links that pre-load data by adding a data URL parameter:

https://codesamplez.com/tools/base64-converter?data=YOUR_BASE64_OR_TEXT_DATA
Code language: JavaScript (javascript)

Examples:

  • Encode mode: ?data=Hello%20World
  • Decode mode: ?data=SGVsbG8gV29ybGQ%3D

How It Works

  1. Add ?data= followed by URL-encoded text or Base64 data
  2. The tool will:
    • Automatically decode the URL parameter
    • Pre-populate the input field with the decoded data
    • Set the mode to “Auto Detect” for smart processing
    • Immediately perform the conversion
  3. The conversion starts instantly when the page loads

URL Encoding Requirements

When creating links, ensure special characters are properly URL-encoded:

  • Spaces become %20
  • Plus signs (+) become %2B
  • Equal signs (=) become %3D
  • Ampersands (&) become %26

From Your Website

You can integrate this into your own applications by creating links like:

<!-- Link to encode "Hello World" -->
<a href="https://codesamplez.com/tools/base64-converter?data=Hello%20World">Encode "Hello World"</a>

<!-- Link with Base64 data to decode -->
<a href="https://codesamplez.com/tools/base64-converter?data=SGVsbG8gV29ybGQ%3D">Decode Base64 string</a>
JavaScript

How Base64 Conversion Works:

Base64 encoding is a method for converting binary data (such as images, files, or any non-text data) into an ASCII string format using a set of 64 characters (A–Z, a–z, 0–9, +, and /). It works by taking input bytes, grouping them into sets of three (24 bits), and then dividing those into four groups of six bits. Each 6-bit group is then mapped to a character from the Base64 alphabet. Padding with = is used if the input data isn’t a multiple of three bytes.

Decoding is the reverse process: the encoded Base64 string is processed in groups of four characters, each mapped back into a 6-bit value and then combined to reconstruct the original bytes.

Example Conversion:

The text ‘Hello’ encodes to SGVsbG8= in Base64. Decoding SGVsbG8= will return ‘Hello’.

Character Encodings

  • UTF-8: Universal character encoding, supports all Unicode characters (default)
  • ASCII: Basic 7-bit encoding, supports English characters and common symbols
  • ISO-8859-1: 8-bit encoding, supports Western European characters
  • UCS-2: Fixed-width 16-bit encoding, supports Basic Multilingual Plane

Automatic Base64 Detection

The tool uses a multi-step validation process to detect Base64 strings:

  1. Length validation (must be multiple of 4)
  2. Character set validation (A-Z, a-z, 0-9, +, /, =)
  3. Padding validation
  4. Decode/encode round-trip verification

Error Handling

The converter includes comprehensive error handling for:

  • Invalid Base64 strings with detailed validation feedback
  • Character encoding issues:
    • ASCII: Replaces non-ASCII characters with ‘?’
    • ISO-8859-1: Handles overflow by masking to 8-bits
    • UCS-2: Validates byte sequences and handles surrogate pairs
    • UTF-8: Detects invalid sequences using TextDecoder
  • Memory-efficient processing of large files using a streaming approach
  • Input validation:
    • Null/undefined input detection
    • Empty string handling
    • Invalid character encoding selection
  • File operations:
    • File reading errors
    • File size limits
    • Unsupported file types
  • Clipboard operations:

Special Features:

UCS-2 Encoding

  • Special handling for surrogate pairs and emoji characters
  • 4-byte sequence detection for extended Unicode characters
  • Fallback handling for basic BMP (Basic Multilingual Plane) characters
  • Maintains character integrity during encode/decode operations

Memory Management

  • Efficient byte array allocation
  • Streaming processing for large files
  • Automatic garbage collection optimization
  • Browser memory limit considerations

Browser Support For Base64 Converter Tool

The tool requires a modern browser that supports:

  • Clipboard API
  • ES6+ JavaScript
  • TextEncoder/TextDecoder APIs
  • File API

Do you have any feature requests or any issues/bugs to report? Feel free to contact us!

Base64 Converter FAQs(Frequently Asked Questions):

Is Base64 encoding secure?

No – Base64 is not encryption. It’s an encoding scheme for data representation, not meant for security. It merely converts data to a text format; it does not hide or protect the data

What are common uses of Base64?

Base64 is commonly used to safely encode binary data for transmission over text-based protocols such as email or URLs. E.g. embedding images in web pages (as data URIs), sending email attachments in SMTP (MIME base64), storing small blobs in JSON or config files, etc.

Does this tool send my data to a server?

No. The conversion happens entirely in the browser (client-side). This means your input is not uploaded, ensuring privacy.