A free online Base64 encoder and decoder that instantly converts text to Base64 and back. Encode strings, decode Base64 payloads, and handle URL-safe Base64 — all running locally in your browser with zero server communication.
Key Features
Encode & Decode — Convert text to Base64 and Base64 back to text
URL-Safe Mode — Handles URL-safe Base64 encoding with - and _ characters
Instant Results — Real-time conversion as you type
Large Text Support — Handles multi-line and large payloads
Copy to Clipboard — One-click copy of encoded or decoded output
100% Client-Side — No data leaves your browser
How to Use
Paste your text or Base64 string into the input textarea.
Click Encode to convert text to Base64, or Decode to convert Base64 back to text.
The result appears instantly in the output area.
Copy the output to your clipboard with the copy button.
Use Cases
Email Attachments:Encode binary data for MIME email attachments that need safe text transport.
API Authentication:Encode username:password pairs for HTTP Basic Authentication headers.
Embedding Data:Embed images or binary data directly in HTML, CSS, or JSON as data URIs.
Debugging:Decode Base64 strings found in logs, APIs, or encoded payloads to inspect their contents.
Tips
Tip: Base64 is NOT encryption — it is an encoding scheme. Anyone can decode it. Never use Base64 alone to protect sensitive data.
Tip: Base64 encoding increases data size by approximately 33%. Keep this in mind when encoding large payloads.
Alternatives
Command Line — echo -n "text" | base64 on Linux/Mac
Python — base64.b64encode(b"text")
VS Code — Extensions like "Base64 encode/decode"
FAQ
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 used to safely transmit binary data over channels that only support text, such as email, URLs, and JSON.
No. Base64 is an encoding, not encryption. It provides no security whatsoever. Anyone can decode a Base64 string in seconds. If you need to protect sensitive data, use proper encryption like AES.
Base64 represents every 3 bytes of binary data using 4 ASCII characters. This results in approximately 33% size increase. This overhead is the trade-off for safely transmitting binary data over text-only channels.
Standard Base64 uses + and / characters which have special meaning in URLs. URL-safe Base64 replaces these with - and _ characters to avoid encoding issues when used in web addresses and query parameters.
Base64 is used in HTTP Basic Authentication, email (MIME), data URIs in HTML/CSS, JWT tokens, embedding images in JSON/XML, and many other protocols that need to transport binary data as text.
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