Skip to main content

Base64 Encoder & Decoder

Encode and decode text, Base64URL, UTF-8 Unicode, and binary files online. 100% private, client-side processing.

Client-Side Privacy Free Forever Mobile & PC
100% Client-Side Privacy: Conversions execute purely in browser memory. No data is uploaded or logged.
44 chars (46 bytes)

Understanding Base64 Encoding

A complete guide to Base64, Base64URL, and binary-to-text encoding systems.

How Base64 Works

Base64 groups 24 bits (3 bytes) of input into four 6-bit numbers, mapping each 6-bit value to an index in a 64-character alphabet (A-Z, a-z, 0-9, +, /). Because 3 bytes become 4 characters, Base64 strings are approximately 33% larger than raw binary.

Base64URL in Web Standards

RFC 4648 Section 5 defines Base64URL for URL and filename safety. By replacing '+' with '-' and '/' with '_', Base64URL avoids conflicts with URL path separators and query parameter delimiters.

Embedding Assets with Data URIs

Data URIs allow developers to embed small icons, SVG files, or audio clips directly into HTML or CSS stylesheets, reducing HTTP round-trip requests for web page optimization.

Our Tool Features

Why developers and engineers prefer this tool for everyday development workflows.

Universal Base64 & Base64URL

Toggle between standard MIME Base64 and URL-safe Base64URL (RFC 4648) with one click.

Full UTF-8 Unicode Support

Correctly handles multi-byte UTF-8 emojis, foreign scripts, and accented characters without mojibake errors.

Binary File & Data URI Export

Upload any image, font, audio, or PDF file to generate instant base64 Data URIs ready for CSS and HTML embedding.

Zero-Latency Client-Side Engine

Computes encodings and decodings locally in browser memory without sending payloads across the internet.

Cross-Device Responsive

Optimized for quick copy-pasting on mobile, tablet, and desktop environments.

Unlimited Free Conversions

No file size paywalls, no login requirements, and no daily quota limits.

How To Use Base64 Encoder & Decoder Online?

Follow these quick steps to get instant, accurate results in seconds.

1

Select Encode or Decode mode

Choose whether you want to convert plain text into Base64 or turn an existing Base64 string back into readable text.

  1. Select 'Encode' to convert text, passwords, or files into Base64.
  2. Select 'Decode' to inspect and extract the underlying data from a Base64 string.
  3. Choose standard Base64 or URL-safe Base64URL depending on your application.
Input Mode SelectionClient-Side
Mode: Encode (UTF-8)
Input: "Hello, World! 🚀"
Character Set: Unicode Compliant
Options: Standard Base64 (Padding = true)
Instant ExecutionReady
2

Paste text or drag-and-drop a file

Type into the editor or upload an image/binary asset directly.

  1. Paste arbitrary text or token strings into the input box.
  2. Or click 'Upload File' to convert PNG, JPG, WebP, SVG, or PDF files into Data URIs.
  3. The conversion runs instantly as you type without pressing submit.
Instant Conversion ProcessingClient-Side
File: logo.png (12.4 KB)
Data URI: data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAA...
Payload Size: 16.5 KB (33% overhead)
Instant ExecutionReady
3

Copy result or download output file

Use the instant copy button or download the converted output.

  1. Click 'Copy' to copy the encoded or decoded string to your clipboard.
  2. When decoding binary files, click 'Download Decoded File' to reconstruct the original asset.
  3. Review input and output character counts to monitor payload overhead.
Export ActionsClient-Side
Output Status: 100% Valid Base64
[ Copy to Clipboard ]   [ Download File ]
Length: 16,532 characters
Instant ExecutionReady

Supported Base64 Formats & Encodings

Reference examples for web development and API payloads.

Standard Base64 (RFC 4648)

MIME / RFC 4648

Standard 64-character alphabet using '+' and '/' with '=' padding.

Example Syntax
SGVsbG8sIFByaXlnb3AgRGV2ZWxvcGVycyE=
Decodes to: 'Hello, Priygop Developers!'

URL-Safe Base64URL

JWT / Web Safe

Replaces '+' with '-' and '/' with '_' to ensure safety in URLs and JWT payloads.

Example Syntax
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9
Decodes to standard JWT header: {'alg':'HS256','typ':'JWT'}

Data URI Scheme

Inline Web Asset

Inline asset format for embedding images directly in HTML <img> tags or CSS stylesheets.

Example Syntax
data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIxNiIgaGVpZ2h0PSIxNiI+PGNpcmNsZSBjeD0iOCIgY3k9IjgiIHI9IjgiIGZpbGw9IiMyMjljNmIiLz48L3N2Zz4=
Renders an inline SVG emerald circle without an HTTP request.

Multi-Byte UTF-8 Emoji String

Unicode

Handles complex multi-byte code points like emojis without truncation or mojibake.

Example Syntax
8J+agCBGaXJlICYgUm9ja2V0IQ==
Decodes to: '🚀 Fire & Rocket!'

Recent Updates & Improvements

Continuously maintained and improved based on developer feedback.

UTF-8 Multi-Byte Text Encoding FixLatest Release

Integrated browser TextEncoder and TextDecoder APIs to guarantee zero corruption when encoding emojis, Asian characters, and accented Latin glyphs.

Base64URL Auto-Detection AddedFeature Added

Added smart regex detection for Base64URL characters ('-' and '_') to automatically switch decoding modes without manual toggles.

Data URI Extraction HelperUI/UX Update

Automatically parses MIME headers from Data URIs when pasted into the decoder box.

Frequently Asked Questions

Related Tools

JWT Debugger

Decode, verify, and generate JSON Web Tokens in the browser. Check HMAC signatures and inspect claims with 100% privacy.

URL Encoder & Decoder

Encode and decode URLs and query string parameters online with full UTF-8 percent-encoding support.

Text Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes simultaneously in real-time. 100% private, client-side Web Crypto.