Base64 Encoder & Decoder

Base64 Encoder & Decoder Tool

Transform any text into Base64 encoded format or decode Base64 strings back to readable text with our free online Base64 encoder and decoder tool. This utility is essential for developers working with data encoding, API authentication, email attachments, data URIs, and secure data transmission. Whether you need to encode binary data for web transfer or decode Base64 strings from APIs, our tool handles it all seamlessly with support for UTF-8 and special characters.

Perfect for encoding images and files for data URIs, working with HTTP Basic Authentication headers, debugging Base64-encoded API responses, processing email attachments, and preparing data for URL-safe transmission. The tool provides real-time encoding and decoding, displays detailed statistics including byte size and character count, and handles Unicode characters correctly. All processing happens locally in your browser with no data sent to external servers, ensuring complete privacy and security for sensitive information.

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It works by converting binary data into a set of 64 different ASCII characters (A-Z, a-z, 0-9, +, and /), making it safe to transmit over text-based protocols like HTTP, email, and JSON. Base64 encoding increases the data size by approximately 33%, but ensures that binary data can be safely embedded in text formats without corruption or misinterpretation by systems that only handle text.

Common uses include embedding images in HTML and CSS using data URIs (data:image/png;base64,...), encoding binary files for JSON APIs, implementing HTTP Basic Authentication (Authorization: Basic base64credentials), sending file attachments in emails, and storing binary data in text-based databases. Base64 decoding reverses this process, converting the encoded ASCII string back to its original binary format or text representation.

How to Use This Base64 Tool

1. Enter or paste your text into the input field, or use the Paste button to paste from clipboard.
2. Click Encode to Base64 to convert plain text into Base64 format, perfect for data URIs, API requests, or secure transmission.
3. Click Decode from Base64 to convert a Base64 string back to readable text. The tool automatically handles UTF-8 and special characters.
4. View the result in the output field with real-time statistics showing size, lines, and character count for both input and output.
5. Use Copy to Clipboard to instantly copy the encoded or decoded result for use in your projects.
6. Click Swap to quickly switch between encoded and decoded versions for iterative testing.
7. Click Clear to reset both input and output fields and start fresh with new data.

Common Use Cases for Base64 Encoding

Why Use Our Base64 Encoder & Decoder?

• ✓Instant Conversion: Encode and decode Base64 strings instantly with real-time processing and immediate results. No waiting, no delays.
• ✓UTF-8 Support: Correctly handles Unicode characters, emojis, and special characters from any language with proper UTF-8 encoding and decoding.
• ✓Bidirectional Conversion: Seamlessly encode text to Base64 or decode Base64 back to text with dedicated buttons and easy swap functionality.
• ✓Detailed Statistics: View file size in bytes/KB, line count, and character count for both input and output to understand data transformation.
• ✓Error Handling: Clear error messages when decoding invalid Base64 strings help you identify and fix issues quickly.
• ✓One-Click Copy & Paste: Quickly paste input from clipboard and copy results with a single click for efficient workflow.
• ✓100% Free & Private: No registration required, unlimited usage, and all processing happens locally in your browser for complete privacy.
• ✓Developer-Friendly Interface: Monospace font, line numbers, and syntax-aware editing provide a professional coding experience.
• ✓Mobile Responsive: Works perfectly on desktop, tablet, and mobile devices with an optimized responsive design for encoding on the go.

Base64 Encoding Best Practices

• •Remember that Base64 increases data size by approximately 33%. Consider gzip compression for large Base64 payloads in APIs.
• •Use URL-safe Base64 variants (Base64url) when encoding data for URLs to avoid issues with special characters like + and /.
• •Base64 is not encryption. Never use Base64 alone to secure sensitive data—use proper encryption algorithms like AES before encoding.
• •When embedding Base64 images in HTML/CSS, consider the trade-off between inline convenience and caching benefits of external files.
• •Always validate and sanitize Base64 input before decoding to prevent injection attacks and malformed data issues in production.
• •Test Base64-encoded data across different systems to ensure proper UTF-8 handling and character encoding compatibility.
• •Document the use of Base64 encoding in your APIs and code to help team members understand data formats and expected structures.
• •For large files, consider chunking the data before Base64 encoding to avoid memory issues and improve processing performance.

Understanding Base64 Character Set

Base64 uses a specific set of 64 characters to represent binary data: uppercase letters A-Z (26 characters), lowercase letters a-z (26 characters), digits 0-9 (10 characters), and two special characters plus (+) and forward slash (/). The equals sign (=) is used as padding to ensure the output length is a multiple of 4 characters. This character set was chosen because these ASCII characters are universally supported across all text-based systems and protocols.

When you see a Base64 string like SGVsbG8gV29ybGQh, each character represents 6 bits of data. Four Base64 characters encode three bytes of original data, which is why Base64 encoding increases size by approximately 33%. The padding characters (=) at the end indicate how many bytes of the original data the last group represents, ensuring proper decoding without data loss.