Base64 Encoder & Decoder
Input
Choose Encode or Decode
Output

Base64 Encoder Decoder Online Free — Encode Files & Images — Free Online Tool

Encode text and files to Base64 online free. Decode Base64 strings back to text. Supports images with live preview. No server upload — all processing in your browser.

Free Forever
No Signup
No Upload
100% Private
Browser-based

Features

Built for real developer workflows. No fluff, just the tools you need.

🔤

Text Encoding

Encode any text to Base64 using UTF-8. Handles Unicode, emoji and all special characters correctly.

📁

File Encoding

Upload any file — PDF, image, binary — and get its Base64 string. The file stays in your browser memory.

🖼️

Image Preview

Pasting a Base64 image string shows a live preview. Instantly verify encoded images without leaving the page.

↩

Decode Any Base64

Paste any Base64 string to decode it back to the original text. Works with standard and URL-safe Base64.

⇄

Swap Input & Output

Flip input and output with one click — encode then immediately decode to verify round-trip accuracy.

🔒

Zero Server Contact

Encoding uses the browser's native btoa() and atob() APIs. Your data never leaves your device.

How to use

Get results in seconds — no account, no file upload required.

1

Paste text or upload a file

Type or paste text into the input panel. Or click Encode File to load any file from your computer.

2

Click Encode or Decode

Encode converts to Base64. Decode converts Base64 back to the original text. Image Base64 shows a preview automatically.

3

Copy the result

Click Copy to copy the output. Paste encoded text directly into APIs, HTML, CSS or configuration files.

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Frequently asked questions

What is Base64?
▾
Base64 encodes binary data as ASCII text using 64 printable characters. It is used in email attachments, data URLs, JWT tokens and HTTP Basic Auth headers.
Why is Base64 output longer?
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Base64 encodes 3 bytes as 4 characters, adding = padding. Output is always about 33% larger than the original input.
Can I encode images?
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Yes. Upload any image file and the tool generates a Base64 string. You can use this as a data:image/png;base64,... URL in HTML or CSS.
Does Base64 encrypt my data?
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No. Base64 is encoding, not encryption. Anyone can decode it instantly. Never use Base64 to protect sensitive data.
Why does decoding fail?
▾
Base64 allows only A-Z, a-z, 0-9, + and /. URL-safe Base64 uses - and _ instead. Remove whitespace and replace - with + and _ with / before decoding.
What is URL-safe Base64?
▾
URL-safe Base64 replaces + with - and / with _ for use in URLs without percent-encoding. This tool decodes both formats correctly.