📌 Use Cases

Base64 is a universal format for encoding binary data as plain text, widely used for email attachments, API data transfer, Data-URI inline images, and JWT / Basic Auth. This tool runs entirely in your browser, supports UTF-8 (including Chinese and emoji), and encodes and decodes instantly without uploading your data — balancing security and speed, ideal for development debugging and everyday text conversion.

📖 Learn More About base64 encoder

Why You Need It

Embed binary data (images, files) directly in text formats like Data URIs, JSON, or CSS.
Send credentials or tokens safely in HTTP headers (Basic Auth, JWT).
Make debugging easier by turning opaque blobs into readable, copy-pasteable text.

How It Works

Base64 encodes every 3 bytes into 4 printable characters using a 64-character alphabet (A–Z, a–z, 0–9, +, /). It is reversible and adds about 33% size overhead — it is encoding, not encryption.

A Quick Example

Paste a small image or any text, choose encode or decode, and copy the result instantly — all in your browser.

Common Mistakes

Treating Base64 as encryption (anyone can decode it).
Forgetting that it grows data size by ~33%.
Mixing up encodeURI vs raw encoding when embedding in URLs.

About the free online Base64 Encoder / Decoder

Looking for a free online Base64 Encoder / Decoder? Base64 is a universal format for encoding binary data as plain text, widely used for email attachments, API data transfer, Data-URI inline images, and JWT / Basic Auth. This tool runs entirely in your browser, supports UTF-8 (including Chinese and emoji), and encodes and decodes instantly without uploading your data — balancing security and speed, ideal for development debugging and everyday text conversion. This tool is completely free and requires no registration — every operation runs locally in your browser, your data is never uploaded to any server, and you can use it anytime just by opening the page.

🔄 Base64 Encoder / Decoder

Encode text to Base64 or decode Base64 back to readable text. Supports UTF-8 characters including Chinese, Japanese, and emoji.

Mode

Input Text

Result

🔒 All processing happens in your browser. No data is uploaded to any server.

📋 How to Use

Select the mode: "Encode" (text to Base64) or "Decode" (Base64 to text).
Type or paste your text into the input box.
The result updates automatically as you type (live mode).
Use "Swap" to move the result to the input and switch modes.
Click "Copy Result" to copy the output to your clipboard.

❓ FAQ

Can it handle Chinese and other Unicode characters?

Yes. The tool uses proper UTF-8 encoding and decoding, so it correctly handles Chinese, Japanese, Korean, emoji, and any other Unicode characters that standard Base64 implementations may struggle with.

Can I encode files to Base64?

Currently, the tool processes text input only. For file-to-Base64 conversion (e.g., creating Data URIs), you can use the browser's File API in combination with this tool. A dedicated file encoding feature is planned.

Is there a size limit?

The limit depends on your browser's available memory. In practice, you can process text up to several megabytes without issues. Very large inputs may cause the browser to become temporarily unresponsive.

What is Base64 used for?

Base64 is commonly used to encode binary data as text, enabling it to be safely transmitted over text-based protocols like email, HTTP, and JSON. It's also used in Data URIs, JWT tokens, and Basic HTTP authentication.

💡 Use Cases

📦

Data URIs

Encode images or files as Base64 Data URIs for inline embedding in HTML/CSS.

📡

API Transmission

Encode binary data for safe transmission in JSON APIs and webhooks.

📧

Email Attachments

Understand and debug Base64-encoded email attachment content.

🔗 Related Tools

📚 Further Reading

Want to go deeper? These tutorials pair well with this tool.

📄What Is Base64? Encoding Principles and Common Uses Explained 📄The Text Toolkit: Clean, Convert & Format in One Click 📄Case & Naming Conventions: camelCase to kebab

Browse all tutorials →