What is Base64 encoding used for?

Base64 converts binary or text data into a safe ASCII string that can be embedded in places that only support plain text — email attachments (MIME), data URIs for images in CSS/HTML, JSON/XML payloads, and HTTP Basic Authentication headers.

Is Base64 encryption or a security measure?

No. Base64 is purely an encoding scheme for safely representing binary data as text — it provides zero confidentiality. Anyone can decode a Base64 string instantly with this tool or a single line of code. Never use Base64 as a substitute for real encryption.

Why does decoding sometimes fail with an error?

Base64 decoding fails when the input contains characters outside the Base64 alphabet (A–Z, a–z, 0–9, +, /, =) or has incorrect padding length. This tool catches that failure and shows a clear error message instead of crashing.

Does this tool handle emoji and non-English text correctly?

Yes. The encoder first converts your text to UTF-8 bytes using the browser's TextEncoder before Base64-encoding, and the decoder reverses this with TextDecoder. This correctly round-trips emoji, accented letters, Chinese, Arabic, and any other Unicode text.

Is my text sent to a server when I encode or decode it?

No. All encoding and decoding happens locally in your browser tab using JavaScript. No network request is made — you can verify this by checking your browser's Network tab while using the tool.

What's the difference between Base64 and URL encoding?

Base64 encodes binary data into a 64-character alphabet optimized for compactness; URL encoding (percent-encoding) escapes only the specific characters that are unsafe in a URL. They solve different problems — Base64 for binary-to-text, URL encoding for making text safe inside a URL. Use our separate URL Encoder/Decoder tool for that.

Why is the Base64 output longer than my original text?

Base64 encodes every 3 bytes of input as 4 output characters, an overhead of roughly 33%. This is an inherent tradeoff of representing arbitrary binary data using only 64 safe printable characters.

Can I encode a whole file, not just text?

This tool is designed for text input pasted directly into the browser. For encoding binary files (images, PDFs) to Base64, you'd need a file-reading tool that converts file bytes to a data URI — that's outside the scope of this text-focused encoder.

What does the '=' padding at the end of a Base64 string mean?

The '=' characters pad the output to a multiple of 4 characters when the input length isn't a multiple of 3 bytes. One or two padding characters may appear at the end depending on the input length; it's a normal, expected part of the format.

Is there a size limit on what I can encode or decode?

There's no hard limit imposed by the tool itself, but very large inputs (multiple megabytes of text) may feel slower since everything runs synchronously in your browser's main thread.

Base64 Encoder & Decoder — Encode or Decode Text Instantly

Our Base64 Encoder / Decoder converts any text to Base64 format or decodes Base64 strings back into readable text, entirely inside your browser using the native btoa/atob APIs wrapped with a UTF-8-safe TextEncoder/TextDecoder pipeline. Toggle between Encode and Decode mode, paste your input, and see the result update instantly. Invalid Base64 input is caught and reported clearly instead of crashing the page. Nothing you type is ever transmitted anywhere — the entire operation runs client-side.

Text to encode

Result

Your encoded or decoded result will appear here

How to Use the Base64 Encoder / Decoder — Free Online Tool

1
Choose Encode to convert plain text to Base64, or Decode to convert Base64 back to plain text.
2
Paste or type your input into the text area.
3
The result appears instantly in the output box below — no button click needed.
4
Click 'Copy' to copy the result to your clipboard.

Why Use Base64 Encoder / Decoder — Free Online Tool?

Base64 is a binary-to-text encoding scheme that represents arbitrary byte data using only 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It's used everywhere in web development: embedding small images directly in CSS or HTML as data URIs, encoding email attachments (MIME), storing binary data in JSON or XML which only support text, and transmitting credentials in HTTP Basic Authentication headers. Base64 is not encryption — it provides no security or confidentiality, only a safe text representation of binary data. This tool uses the browser's native TextEncoder and TextDecoder APIs to correctly round-trip Unicode text (emoji, accented characters, non-Latin scripts) through UTF-8 bytes before encoding, avoiding the corruption that naive btoa()/atob() calls produce on non-ASCII input. Decoding invalid Base64 (wrong padding, invalid characters) is caught and surfaced as a clear error rather than throwing an unhandled exception.

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