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Free Base64 Encoder & Decoder Online

Convert text and files to Base64 and back, entirely in your browser. Supports UTF-8 text and any file type via the file picker.

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  • Runs in your browser
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Guide

What is Base64 encoding?

Base64 is a way of representing binary data using only 64 printable ASCII characters (A to Z, a to z, 0 to 9, plus "+" and "/"). It works by taking three bytes (24 bits) at a time and splitting them into four 6-bit groups, each mapped to one of those 64 characters. The result is text that can travel safely through systems that were designed for text and might otherwise corrupt raw binary.

When should you use Base64?

Base64 shows up wherever binary data needs to ride inside a text-only channel: embedding small images in CSS or HTML with data URIs, attaching files to email (MIME), encoding credentials in HTTP Basic Auth, and storing binary blobs in JSON or XML. It is the standard answer to "how do I put bytes where only text is allowed".

Base64 is not encryption

A crucial point: Base64 is encoding, not encryption. It provides no security whatsoever. Anyone can decode it back to the original in seconds, exactly as this tool does. It only changes the representation of data, not its secrecy. Never use Base64 to "hide" passwords or sensitive information; use real encryption for that.

Size overhead

Because Base64 represents 3 bytes with 4 characters, encoded data is about 33% larger than the original, plus a little padding. That tradeoff (bigger size in exchange for text-safety) is why you embed only small assets as Base64 and link to larger ones normally. This tool encodes and decodes both typed text and any file you select, entirely in your browser, so nothing is uploaded.

Last updated: July 2026

Frequently Asked Questions

What is Base64 encoding?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters. It is widely used for embedding binary data in HTML, CSS, JSON, and email.
When should I use Base64 encoding?
Use Base64 when you need to embed binary data (images, files) in text-based formats like JSON or XML, or when transmitting data over protocols that don’t support binary.
Does Base64 make data secure?
No. Base64 is encoding, not encryption. Encoded data can be trivially decoded by anyone. Use it for compatibility, not security.
What is the size overhead of Base64?
Base64 increases data size by approximately 33%.
Is Base64 the same as encryption?
No. Base64 is a lossless encoding format. Anyone can decode a Base64 string without a key.