Base64 Encoder & Decoder
Last Updated: June 18, 2026
Drop file here
Waiting for input
Type or paste text, upload a file, or drag and drop to see the encoded or decoded result.
Output
All encoding and decoding happens directly in your browser. Your files and data never leave your device.
Encode text, files, and images to Base64 format. Decode Base64 back to original content. Browser-based with image preview and file upload support.
How To Use
Follow these simple steps to get started with base64 encoder & decoder.
Choose mode
Select Encode to convert text/files to Base64, or Decode to convert Base64 back to original content.
Enter input
Type or paste text, upload a file, or drag and drop an image to process.
Process instantly
Click Encode or Decode — the result appears instantly with character count and byte size.
Copy or download
Copy the encoded/decoded content to your clipboard or download it as a file.
Real-World Examples
Practical situations where base64 encoder & decoder helps solve real problems.
Web Development
Encode binary data for embedding in CSS, HTML, or JavaScript. Decode API tokens and authentication headers.
Image Embedding
Convert images to Base64 data URLs for inline embedding in HTML, CSS, or JSON payloads.
Data Transmission
Prepare binary data for transmission in systems that require ASCII encoding, such as email attachments and JSON APIs.
Why Use This Tool
Discover how this tool can improve your workflow and productivity.
Two-Way Conversion
Encode text, files, and images to Base64 and decode Base64 back to original content with full accuracy.
File & Image Support
Upload any file type — images, PDFs, documents — and instantly get its Base64 string or data URL with preview.
URL Safe Mode
Toggle URL-safe Base64 that replaces + and / with - and _ for safe use in URLs and filenames.
Privacy First
All encoding and decoding happens in your browser. Your files and data never leave your device.
Common Use Cases
Practical scenarios where this tool can help you get things done.
Web Development
Encode binary data for embedding in CSS, HTML, or JavaScript. Decode API tokens and authentication headers.
Image Embedding
Convert images to Base64 data URLs for inline embedding in HTML, CSS, or JSON payloads.
Data Transmission
Prepare binary data for transmission in systems that require ASCII encoding, such as email attachments and JSON APIs.
Tool Summary
Quick facts about this tool at a glance.
What Is Base64 Encoder & Decoder?
A Base64 encoder and decoder is a browser-based utility that converts binary data, text, and files into Base64 ASCII representation and decodes Base64 strings back to their original form. It supports text encoding, file uploads, image preview, URL-safe mode, and character statistics — all processed locally in the browser without any server interaction.
About This Tool
Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format using 64 characters: A-Z, a-z, 0-9, +, and /. It is one of the most widely used encoding mechanisms on the web, powering everything from email attachments (MIME) to embedded images in HTML and CSS.
What This Base64 Tool Does
This tool provides complete Base64 encoding and decoding capabilities. You can encode plain text into Base64, decode Base64 strings back to readable content, convert images and files to Base64 data URLs, validate Base64 input, and use URL-safe encoding for web-safe output. File upload supports all browser-compatible file types including images, PDFs, documents, and more.
How It Works
For text encoding, the tool uses JavaScript's btoa() function with proper UTF-8 handling via TextEncoder to ensure correct encoding of Unicode characters, emoji, and international text. For decoding, atob() with TextDecoder converts Base64 back to the original string. For file encoding, the FileReader API reads the file as a data URL, producing a Base64 string with the MIME type prefix. URL-safe mode replaces + with - and / with _ before output. All operations happen synchronously or via efficient async file reading to maintain UI responsiveness. Image preview uses the data URL directly in an img element to show the decoded content instantly.
Who Uses Base64 Encoding
Web developers encode images as Base64 data URLs to reduce HTTP requests by embedding small images directly in CSS and HTML. API developers decode Base64-encoded authentication tokens, payloads, and response bodies during integration and debugging. Email system implementers use Base64 for MIME attachments to ensure binary files survive text-only email channels. Security engineers understand the difference between encoding (Base64) and encryption when designing data protection strategies. Students and learners use Base64 tools to understand encoding concepts and experiment with data representation.
Key Features
- • Encode/Decode Toggle: Switch between encoding and decoding modes instantly
- • Text Encoding: Convert plain text to Base64 with UTF-8/Unicode support
- • File Upload: Upload any file type to generate a Base64 data URL
- • Image Preview: See image previews for encoded and decoded image Base64
- • URL Safe Mode: Replace +/ with -_ for URL-compatible Base64
- • Character Statistics: Input/output character count, byte size, and size change
- • Drag & Drop: Drag and drop files directly onto the input area
- • Copy & Download: One-click copy or download as base64.txt or decoded.txt
- • Validation: Validate Base64 input and show clear error messages
- • No Data Upload: All processing stays in your browser — nothing is sent to any server
Quick Summary
This free Base64 Encoder & Decoder converts text, files, and images to and from Base64 format entirely in your browser. Encode plain text, upload images for data URL generation, or decode Base64 strings back to readable content. Features include URL-safe Base64 mode (replacing +/ with -_), image preview for decoded Base64 images, drag-and-drop file upload, character and byte statistics, and one-click copy or download. The tool handles UTF-8, Unicode, and emoji characters correctly using native btoa()/atob() with TextEncoder/TextDecoder wrappers. No data is uploaded to any server.
Related Concepts
Explore related terms and topics associated with base64 encoder & decoder.
Frequently Asked Questions
Common questions about base64 encoder & decoder.
What is Base64 encoder?
A Base64 encoder is a tool that converts binary data or text into a Base64-encoded ASCII string representation. It takes any input — text, images, files — and transforms it into a sequence of 64 different characters (A-Z, a-z, 0-9, +, /) that can be safely transmitted over text-based protocols like HTTP, email, and JSON.
What does a Base64 encoder do?
A Base64 encoder converts binary data into a portable ASCII string format. It processes input in 3-byte groups and converts them into 4 Base64 characters. If the input length is not divisible by 3, padding characters (=) are added. The result can be safely embedded in HTML, CSS, JSON, URLs, and email attachments without corruption.
What is the Base64 encoder code?
In JavaScript, the built-in btoa() function encodes strings to Base64, and atob() decodes Base64 back to text. For files and binary data, the FileReader API with readAsDataURL() generates Base64 data URLs. Modern TextEncoder/TextDecoder APIs handle UTF-8 and Unicode characters properly.
Is Base64 encoding or decoding?
Base64 is an encoding scheme, not encryption or hashing. Encoding transforms data into a different representation using a reversible algorithm. Unlike encryption, Base64 offers no security — anyone can decode Base64 back to the original content without a key. It is designed for data portability, not protection.
How do I Base64 encode a file?
Select a file using the upload button or drag and drop it onto the tool. The file is read locally using the FileReader API and converted to a Base64 data URL. You can copy the resulting string or download it as a text file. Image files also show a preview of the encoded content.
What is an example of Base64?
The text "Hello World" encodes to Base64 as "SGVsbG8gV29ybGQ=". Each 3 bytes of original data becomes 4 Base64 characters. The "=" at the end is padding added because the 11-byte input is not divisible by 3. Longer inputs produce longer Base64 strings, increasing size by approximately 33%.
Why is Base64 so popular?
Base64 is popular because it solves a fundamental problem: many systems (email, HTTP, JSON) are designed to handle text, not binary data. Base64 converts any binary data into safe ASCII text that can be transmitted, stored, and embedded without corruption. It is universally supported across programming languages and platforms.
Is Base64 encode safe?
Base64 is safe for data transmission but not for security. It prevents data corruption when binary data passes through text-only channels, but it does not provide confidentiality. Base64-encoded data can be decoded by anyone without a key. For sensitive data, use encryption (like AES) before encoding to Base64.
Is Base64 a coding language?
No. Base64 is not a programming language — it is an encoding scheme. It defines how binary data is represented using 64 printable ASCII characters. Think of it as a data format or representation, similar to how hexadecimal represents bytes as two-character hex strings. Any programming language can encode and decode Base64.
What does == mean in Base64?
The == at the end of a Base64 string indicates padding. Base64 processes data in 3-byte groups. When the input length is not divisible by 3, the final group has fewer than 3 bytes, and padding characters are added. One byte missing produces ==, two bytes missing produces a single =. Valid Base64 always has a length divisible by 4.
Related Tools
Explore more tools that complement this utility.
URL Encoder & Decoder
Encode text to URL-safe format and decode percent-encoded URLs back to readable text. Supports UTF-8, Unicode, and SVG encoding.
JSON Formatter
Format, beautify, minify, and validate JSON data instantly with syntax highlighting, error detection, and tree view.
JWT Decoder & Local Verifier
Decode and inspect JSON Web Tokens (JWT) entirely in your browser. Verify signatures locally with HS256/384/512, RS256/384/512, or ES256/384/512. Analyze claims, validate expiration times, check for security risks, and simulate clock skew with 100% offline, zero-knowledge privacy.
People Also Searched For
Explore related tools commonly used alongside this utility.
Markdown Live Editor
Write, edit, and preview Markdown in real time. Export rendered HTML or download your Markdown files. Full GFM support with live preview.
CSV Column Matcher
Fuzzy match two CSV columns online free — reconcile messy datasets with Levenshtein distance. Find near matches, typos, and inconsistencies across CSV columns in your browser with no uploads.
JSON Array Diff Tool
Compare two JSON arrays or deeply nested objects instantly in your browser with a recursive diff engine. Detect added, removed, and modified keys in API responses, configuration files, and massive enterprise datasets — all locally with zero uploads.
Markdown Checkbox List Extractor
Extract checked, unchecked, or all tasks from Markdown documents. Supports Obsidian, Notion, GitHub, GitLab, Logseq exports, and more. Fast regex-based parsing, Web Worker offloading, 100% browser-based — no uploads, complete privacy.
Domain Name Extractor & Comparator
Extract root domains from URLs and compare two lists instantly in your browser. Parse millions of URLs, normalize domains, strip subdomains, find shared and unique domains — all locally with no uploads.
Reviewed by FreeDeskTools Editorial Team
Base64 Encoder & Decoder has been reviewed for accuracy, usability, privacy, and browser-side performance. FreeDeskTools tools are designed to run locally whenever possible, helping users complete tasks quickly without unnecessary data collection.
Was this tool helpful?
Your feedback helps us improve Base64 Encoder & Decoder and build better tools for everyone.