Base64 Encoder & Decoder

▸ Input Type

Ready to encode or decode 0 bytes

▸ Text to Encode

URL-Safe Base64 (use - and _ instead of + and /) Chunked Output (76 chars per line, MIME standard)

▸ Base64 Output

▸ Quick Actions

▸ How to Use with Files & Images

📄 Working with Files

HTML, JSON, XML, etc.

To Encode:

Click "File" tab → Upload your file → Click "Encode"

Result:

Base64 text appears in the output area

To Download:

Click "Download" button to save as .txt file

To Decode:

Switch to "Decode" mode → Paste Base64 text → Click "Decode"

Save Original:

Click "Download" and rename file with original extension

(e.g., rename "decoded.txt" to "myfile.html")

💡 Tip: The download gives you a text file - just rename it with the correct extension (.html, .json, .xml, etc.)

🖼️ Working with Images

PNG, JPG, GIF, SVG, WebP

To Encode:

Click "Image" tab → Upload your image → Click "Encode"

Result:

Base64 string appears in output

(starts with "data:image/png;base64,")

To Use:

Copy this entire string and paste it into HTML/CSS as a data URI

Example:

<img src="data:image/png;base64,iVBORw0KG...">

⚠️ Note: For images, you typically don't decode back to a file. Instead, use the Base64 string directly in your HTML/CSS as a data URI. To get the image back, paste the data URI into a browser address bar or use an online converter.

💻 Common Use Cases

When Base64 is useful

Email Attachments

Encode files to include in JSON/XML

Inline Images

Embed small images directly in HTML/CSS

API Data

Send binary files as text through REST APIs

Data URLs

Create self-contained HTML files with embedded images

⚠️ Important Limitations

Things to keep in mind

Base64 increases file size by ~33%

Not encryption

Anyone can decode it easily

Large files (>5MB) may slow down your browser

When decoding files, remember to rename with correct extension

Images as data URIs work best for small files (<100KB)< /strong>

▸ What is Base64?

📖 Definition

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It uses 64 characters (A-Z, a-z, 0-9, +, /) to encode data.

🎯 Common Uses

Embedding images in HTML/CSS

Encoding data in JSON/XML

Email attachments (MIME)

Data URLs for browser

Storing binary data in text fields

⚡ Features

100% client-side processing

No data sent to servers

Instant encoding/decoding

Supports files up to 10MB

Works completely offline

💡 Tips

Base64 increases size by ~33%

Not encryption (easily reversible)

Use for data transmission, not security

Combine with compression for efficiency

🔤 What is Base64?

Base64 is a binary-to-text encoding scheme that converts binary data (like images, files, or any non-text data) into a text format using only 64 ASCII characters. These characters are: A-Z, a-z, 0-9, +, and /.

Think of Base64 as a translator that converts data that computers understand (binary) into a format that text-based systems can safely handle. It's not encryption—anyone can decode it—but it's essential for transmitting binary data through systems designed for text.

Why Base64 exists:

Text-Safe: Converts binary data to plain text that won't break email, JSON, or XML
Universal: Works across all platforms and programming languages
Reliable: Prevents data corruption when sending files through text-only channels
Embeddable: Allows images and files to be embedded directly in HTML, CSS, or JSON

Common applications include embedding images in HTML (data URIs), sending file attachments in JSON APIs, encoding email attachments (MIME), and storing binary data in text-based databases.

Important: Base64 increases file size by approximately 33%. A 100KB file becomes ~133KB when Base64-encoded. This is the trade-off for text compatibility.

🛠️ How to Use This Tool

Getting Started

Choose your mode and input type:

Encode Mode: Convert text, files, or images to Base64
Decode Mode: Convert Base64 back to original format
Text Input: For plain text, JSON, code, or any string data
File Input: For documents, HTML, XML, or any file type
Image Input: For PNG, JPG, GIF, SVG, or WebP images

Encoding Text

Step 1: Select "Encode" mode and "Text" input type

Step 2: Type or paste your text into the input area

Step 3: Click "Encode" button

Step 4: Copy the Base64 output or download it as a file

Encoding Files

Step 1: Select "Encode" mode and "File" input type

Step 2: Click the upload area or drag & drop your file

Step 3: Click "Encode" button

Step 4: The Base64 text appears in the output—copy or download it

Encoding Images (Data URIs)

Step 1: Select "Encode" mode and "Image" input type

Step 2: Upload your image file

Step 3: Click "Encode" button

Step 4: The output includes the complete data URI (data:image/png;base64,...)

Bonus: Use the quick copy buttons to get HTML, CSS, or raw data URI format

Decoding Base64

Step 1: Switch to "Decode" mode

Step 2: Paste your Base64 string into the text input

Step 3: Click "Decode" button

Step 4: Download the result and rename with the correct file extension

Example: Rename "decoded.txt" to "document.pdf" or "image.png"

Advanced Options

URL-Safe Base64: Replaces + and / with - and _ for use in URLs and filenames. Essential for query parameters and file paths.

Chunked Output: Adds line breaks every 76 characters (MIME standard). Required for email attachments and some legacy systems.

Copy Format Options

Click the dropdown next to "Copy" to get Base64 in different formats:

Raw Base64: Just the encoded string
JSON Property: "data": "base64string" format
XML Element: <data>base64string</data> format
JS String: const data = "base64string";
Python Bytes: data = b"base64string"

🔒 Privacy First: All encoding and decoding happens in your browser. Your files never leave your device—no uploads, no servers, no tracking.

💡 Common Use Cases

Embedding Images in HTML/CSS

Convert images to data URIs to embed them directly in your HTML or CSS. This eliminates separate HTTP requests and creates self-contained files. Perfect for email templates, single-page apps, or offline HTML documents.

API Data Transfer

Send files through REST APIs that only accept JSON or XML. Encode your PDF, image, or document to Base64, include it in your JSON payload, and the receiving server can decode it back to the original file.

Email Attachments (MIME)

Email systems use Base64 to encode attachments. When you attach a file to an email, it's converted to Base64 text before transmission. Use chunked output (76 chars/line) for MIME compliance.

Storing Binary Data in Databases

Some databases or text fields can't handle binary data directly. Base64 lets you store images, PDFs, or any file as text in VARCHAR or TEXT columns. Useful for simple storage without blob fields.

Configuration Files

Embed small images, certificates, or keys directly in config files (JSON, YAML, XML). This keeps everything in one file and simplifies deployment—no separate asset management needed.

Data URLs for CSS

Inline small images (icons, backgrounds) in CSS using data URIs. This reduces HTTP requests and speeds up page load. Best for images under 10KB to avoid bloating your stylesheet.

JWT Tokens

JSON Web Tokens use Base64 URL-safe encoding for their payload and signature. Decode JWT tokens to inspect claims and user data without special tools.

Obfuscating Text (Not Security!)

Hide email addresses or text from casual viewing and web scrapers. Remember: Base64 is NOT encryption—anyone can decode it easily. Use only for light obfuscation, never for security.

⚡ Tips & Tricks

Size Matters

Base64 increases file size by ~33%. A 100KB image becomes 133KB. For large files, consider compression before encoding, or use direct file transfer instead of Base64 if possible.

When to Use URL-Safe Encoding

Always use URL-safe Base64 for query parameters, filenames, or anywhere the string might appear in a URL. Standard Base64 uses + and / which have special meaning in URLs.

Data URI Best Practices

Keep data URIs under 100KB for best performance. Browsers can handle larger, but page load and rendering slow down significantly. Use external files for large images.

Decoding Files: Remember Extensions

When decoding Base64 back to a file, the download gives you a .txt file. Rename it with the correct extension (.pdf, .png, .docx, etc.) to open it properly.

Combine with Compression

For large text or JSON data, compress with gzip before Base64 encoding. This can dramatically reduce the final size. Decompress after decoding.

Testing and Validation

After encoding important files, decode them immediately to verify the process worked correctly. This catches any issues before you use the encoded data in production.

Base64 is NOT Encryption

Never use Base64 for security. It's trivially reversible—anyone can decode it in seconds. Use proper encryption (AES, RSA) for sensitive data, then Base64-encode if needed for transport.

Browser Limits

While this tool supports files up to 10MB, very large files (>5MB) may slow down your browser. For production use, consider server-side encoding for large files.

Quick Copy Formats

Use the copy format dropdown to get Base64 in the exact format you need. This saves time reformatting for JSON APIs, XML documents, or code snippets.

❓ Frequently Asked Questions

Is my data safe?

Absolutely. This tool runs 100% in your browser. Your files, images, and text never leave your device. No uploads, no servers, no data collection. Perfect for sensitive documents.

Why does Base64 make files bigger?

Encoding overhead. Base64 uses 6 bits per character but stores 8 bits per byte. This 6:8 ratio creates a ~33% size increase. It's the price for text compatibility.

Can I decode a Base64 image back to a file?

Yes, but... For images, you typically don't decode back to a file. Instead, use the Base64 data URI directly in HTML/CSS. If you need the file, paste the data URI into a browser address bar and save the image.

What's the difference between standard and URL-safe Base64?

Characters used. Standard uses + and / which break URLs. URL-safe replaces them with - and _ so the string works in URLs, filenames, and query parameters without escaping.

Why use chunked output?

MIME compliance. Email systems and some legacy software expect Base64 in 76-character lines. Chunked output adds line breaks for compatibility. Modern web apps usually don't need this.

Can I encode multiple files at once?

Yes! In File mode, you can select or drag multiple files. Each file gets encoded separately with its own output section.

How do I use Base64 images in HTML?

Use the data URI in an img tag: <img src="data:image/png;base64,iVBORw0KG..." />. Or in CSS: background-image: url(data:image/png;base64,...);

Is Base64 encryption?

No. Base64 is encoding, not encryption. Anyone can decode it instantly. It's for data format conversion, not security. Use AES or RSA for actual encryption.

What's the file size limit?

10MB per file. This is a browser memory limit. Larger files may crash the tab. For files over 10MB, use server-side encoding or split into chunks.

Why does my decoded file have the wrong extension?

Manual rename needed. The tool downloads as .txt because it doesn't know the original file type. Rename it with the correct extension (.pdf, .png, .html, etc.) to open it properly.

Can I use this offline?

Yes! Once the page loads, everything works offline. No internet connection needed. Perfect for air-gapped systems or working on planes.

How do I report bugs or request features?

Visit our Contact page to send feedback. We're constantly improving based on user input!

BASE64 Encoder & Decoder

▸ Input Type

▸ Text to Encode

▸ File Upload

▸ Image Upload

▸ Base64 Output

▸ Live Data URI Preview

▸ Quick Actions

▸ How to Use with Files & Images

📄 Working with Files

🖼️ Working with Images

💻 Common Use Cases

⚠️ Important Limitations

▸ What is Base64?

📖 Definition

🎯 Common Uses

⚡ Features

💡 Tips

🔤 What is Base64?

🛠️ How to Use This Tool

Getting Started

Encoding Text

Encoding Files

Encoding Images (Data URIs)

Decoding Base64

Advanced Options

Copy Format Options

💡 Common Use Cases

Embedding Images in HTML/CSS

API Data Transfer

Email Attachments (MIME)

Storing Binary Data in Databases

Configuration Files

Data URLs for CSS

JWT Tokens

Obfuscating Text (Not Security!)

⚡ Tips & Tricks

Size Matters

When to Use URL-Safe Encoding

Data URI Best Practices

Decoding Files: Remember Extensions

Combine with Compression

Testing and Validation

Base64 is NOT Encryption

Browser Limits

Quick Copy Formats

❓ Frequently Asked Questions

Is my data safe?

Why does Base64 make files bigger?

Can I decode a Base64 image back to a file?

What's the difference between standard and URL-safe Base64?

Why use chunked output?

Can I encode multiple files at once?

How do I use Base64 images in HTML?

Is Base64 encryption?

What's the file size limit?

Why does my decoded file have the wrong extension?

Can I use this offline?

How do I report bugs or request features?