How to use Base64 Encoder/Decoder
This is the Base64 Encoder/Decoder utility. 100% client-side and offline capable.
Base64 Encoder/Decoder
Base64 Converter
Encode text, decode Base64, and convert files - 100% client-side, secure & private
All processing happens locally in your browser. No data is ever sent to any server.
How Base64 Encoding Works
1
Input Processing
Text is converted to UTF-8 bytes
2
Binary Grouping
Bytes are grouped into 24-bit blocks
3
6-bit Split
Each block is split into 6-bit groups
4
Character Mapping
6-bit values mapped to Base64 alphabet (A-Z, a-z, 0-9, +, /)
Base64 Character Table
Input
Auto-detect
0 chars
|
0 bytes
Output
Ready
0 chars
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Ratio: 0%
File → Base64
Drag & Drop File Here
or click to browse
Supports: Images, PDF, Audio, Video, ZIP, and moreBase64 → File
Batch Conversion
Process multiple files or text items at once
Drop Multiple Files Here
or click to browse
Data URI Generator
Create Data URIs for embedding files directly in HTML/CSS
Generate Data URI
Drop file here or click to browse
Parse Data URI
Copied to clipboard!
Common Questions
What is Base64 encoding and why is it used?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It's widely used for email attachments (MIME), embedding images in HTML/CSS, storing binary data in JSON/XML, URL parameters, JWT tokens, and API data transfer. Base64 ensures binary data can be safely transmitted over text-based protocols without corruption.
Is my data safe when using this Base64 converter?
100% Private & Secure. All encoding and decoding happens entirely in your browser (client-side) using JavaScript. Your text, files, and sensitive data are never uploaded to any server. We don't use cookies, tracking, or external APIs. This makes our tool completely safe for encoding passwords, credentials, API keys, or any confidential information.
What features does this Base64 tool include?
Our comprehensive Base64 Converter includes: Text ↔ Base64 encoding/decoding with UTF-8 support, File ↔ Base64 conversion (images, PDFs, audio, video, ZIPs), Batch processing for multiple files or text items, Data URI generator with HTML/CSS code snippets, URL-safe encoding (for JWTs and URLs), Auto-detection of input type, Real-time validation, Character/size counters, Line break options (MIME format), and an Educational mode showing step-by-step encoding with the Base64 character table.
How do I convert a file (image/PDF) to Base64?
Navigate to the File tab, then drag & drop your file (or click to browse). Click "Convert to Base64"—the tool reads the file locally using JavaScript's FileReader API and outputs the Base64 string. You can copy the result or download it as a text file. Supported formats include: Images (PNG, JPEG, GIF, WebP, SVG), Documents (PDF, TXT, HTML, JSON), Audio (MP3, WAV, OGG), Video (MP4, WebM), and Archives (ZIP, 7z).
How do I decode Base64 back to a file?
In the File tab's "Base64 → File" section, paste your Base64 string (raw or as a Data URI like data:image/png;base64,...). The tool auto-detects the MIME type from the Data URI or file signature. Enter a filename and click "Download File". The browser will reconstruct the original binary file from the Base64 data and trigger a download—all happening locally without any server processing.
What is URL-safe Base64 encoding?
URL-safe Base64 replaces characters that have special meaning in URLs: + becomes - and / becomes _. Padding characters (=) are often removed. This variant is essential for: JWT tokens (JSON Web Tokens), URL query parameters, cookies, and filenames. Enable the "URL-Safe Encoding" option to automatically apply this transformation. Our tool handles both encoding and decoding of URL-safe Base64.
What is a Data URI and how do I generate one?
A Data URI (or Data URL) embeds file data directly in HTML/CSS using the format: data:[MIME-type];base64,[encoded-data]. For example: data:image/png;base64,iVBORw0KGgo.... Navigate to the Data URI tab, upload your file, and click "Generate Data URI". The tool provides ready-to-use code snippets for HTML img tags and CSS background-image properties—perfect for embedding small images without extra HTTP requests.
How does the step-by-step encoding view work?
Click the Learn Mode button (graduation cap icon) to see exactly how Base64 encoding works. As you type, the tool shows: (1) Original text, (2) UTF-8 bytes, (3) Binary representation (8-bit), (4) 6-bit groups, and (5) Mapped Base64 characters. An interactive Base64 Character Table displays all 64 characters with their index values. This educational feature is perfect for students learning cryptography, developers understanding data encoding, and security professionals.
Can I process multiple files or text items at once?
Yes! The Batch tab supports two modes: Multiple Files—drag & drop or select multiple files, then click "Convert All" to encode them sequentially with progress tracking. Multiple Text Items—enter items one per line and encode or decode them all at once. Results can be copied or downloaded as a text file. This is ideal for bulk data encoding, API testing, or preparing multiple assets.
Does Base64 encoding encrypt or secure my data?
No, Base64 is NOT encryption. It's an encoding scheme, not a security mechanism. Anyone can decode Base64 data instantly—there's no secret key involved. Base64 is designed for data transport and format compatibility, not confidentiality. If you need to protect sensitive data, use proper encryption (like AES) first, then Base64-encode the encrypted result for safe transmission.
Does this Base64 converter work offline?
Yes, 100% Offline. Once the page loads, all encoding, decoding, file conversion, and batch processing work without any internet connection. The tool uses native JavaScript functions (btoa(), atob(), TextEncoder/Decoder, FileReader API) that run entirely in your browser. This makes it perfect for use in secure environments, air-gapped systems, or areas with limited connectivity.