Free Online Base64 Encoder
Batch encode text, files, and images to Base64 format instantly
Instant
Private
Batch Mode
ZIP Download
Data URI
Text
File
Batch
Drag & drop a file here
or click to select a file
filename.txt
(0 KB)
Drag & drop multiple files here
or click to select files (max 20)
Queue (0)
Need to Decode Instead?
Use our dedicated Base64 Decoder for text, file, and image decoding.
Base64 Decoder
How to Use the Base64 Encoder
Encoding Text
- Enter your text in the input area or paste from clipboard.
- Click "Encode to Base64" to convert the text.
- Copy or download the encoded output.
Encoding Files
- Switch to File mode using the tab above.
- Drag and drop a file or click to select one.
- Click "Encode" and the file content will be converted to Base64.
- Enable "Data URI" to get a ready-to-use data URI with MIME type prefix.
Batch Encoding
- Switch to Batch mode.
- Drag in up to 20 files to queue them for encoding.
- Click "Encode to Base64".
- Download a ZIP archive containing separate text files with Base64 contents.
When to Use Base64 Encoding
- Embed images in HTML/CSS: Convert small images to data URIs to reduce HTTP requests.
- Email attachments: MIME encoding requires Base64 for binary attachments.
- API payloads: Send binary data as Base64 strings in JSON APIs.
- Configuration files: Store binary data in text-based configs (YAML, JSON, XML).
- Data storage: Store binary content in text-only databases.
Tip: Base64 increases data size by ~33%. Only use it when you need to transmit binary data through text-only channels.
Frequently Asked Questions
Base64 encoding is used whenever you need to represent binary data (images, files, executable code) as plain text. Common use cases include embedding images in HTML/CSS using data URIs, sending binary attachments in email (MIME encoding), transmitting binary data in JSON API payloads, and storing binary content in text-based configuration files or databases.
Yes! Switch to File mode, then drag and drop any file or click to browse. The tool reads the file locally in your browser using the FileReader API and converts its binary content to a Base64 string. For images, you can enable the Data URI option to get a complete data URI with the correct MIME type, ready to paste directly into HTML or CSS.
URL-safe Base64 (defined in RFC 4648) replaces the + character with - and / with _, making the encoded string safe to use in URLs, query parameters, and filenames. Standard Base64's + and / characters have special meaning in URLs and would need to be percent-encoded. Enable the URL-safe option when your Base64 output will be used in web addresses or file paths.
Your data stays completely private. All encoding is performed locally in your browser using JavaScript's built-in btoa() function and the FileReader API. Nothing is uploaded to our servers or any third party. The tool works entirely offline after the page loads, so you can safely encode sensitive data like API keys, passwords, or confidential documents.
Base64 encoding increases data size by approximately 33%. This is because every 3 bytes of input are represented as 4 characters of output (each character represents 6 bits instead of 8). For example, a 1 MB file would produce approximately 1.37 MB of Base64 text. Keep this overhead in mind when deciding whether to use Base64 for large files.