Base64エンコーダー | Fairmont AI

無料Base64エンコーダー。

Our free online Base64 encoder and decoder lets you quickly convert text to Base64 format and back again. Base64 encoding is widely used across the web for embedding binary data in text-based formats such as HTML, CSS, JSON, and XML. Whether you need to encode data for API requests, create data URIs for inline images, handle email attachments with MIME encoding, or decode Base64 strings received from web services, this tool makes it simple and instant. No registration or software installation required. Just paste your text or Base64 string, and get your result in real time. Our tool supports full Unicode text, handles special characters gracefully, and provides clear error messages for invalid input.

How to Encode or Decode Base64

  1. Choose Encode or Decode Mode: Select whether you want to encode plain text into Base64 format or decode an existing Base64 string back into readable text. You can easily switch between modes at any time.
  2. Enter or Paste Your Text: Type or paste the text you want to convert into the input field. The tool accepts any text input including Unicode characters, special symbols, and multi-line content.
  3. View Your Instant Result: The converted output appears instantly as you type. Copy the result to your clipboard with one click, or use the swap button to quickly reverse the conversion.

Frequently Asked Questions

What is Base64 encoding?

Base64 is a binary-to-text encoding scheme that represents binary data using a set of 64 ASCII characters (A-Z, a-z, 0-9, +, /). It is commonly used to encode data that needs to be transmitted over text-based protocols, ensuring the data remains intact and unmodified during transport.

Is Base64 encoding the same as encryption?

No, Base64 encoding is not encryption and provides no security. It is simply a way to represent binary data as text. Anyone can decode a Base64 string back to its original form. For security, you should use proper encryption algorithms like AES or RSA.

Why does Base64 increase the data size?

Base64 encoding increases the data size by approximately 33%. This is because every 3 bytes of binary data are represented as 4 Base64 characters. The trade-off is that the data becomes safe to transmit over text-only channels.

Can I encode files with this tool?

This tool is designed for text-to-Base64 and Base64-to-text conversion. For encoding binary files like images or documents, you would typically use a file-based Base64 encoder or a programming language's built-in Base64 library.

What characters are used in Base64?

Standard Base64 uses 64 characters: uppercase letters (A-Z), lowercase letters (a-z), digits (0-9), plus (+), and forward slash (/). The equals sign (=) is used as padding. Base64URL, a variant used in URLs, replaces + with - and / with _.

Is my data safe when using this tool?

Yes, all encoding and decoding happens entirely in your browser using JavaScript. Your data is never sent to any server, ensuring complete privacy and security of your information.