Free Base64 Encode / Decode

How to Encode and Decode Base64

Type or paste plain text in the left panel and the Base64-encoded output appears instantly on the right. To decode, paste a Base64 string in the right panel and the original text appears on the left. The tool handles Unicode by first encoding text to UTF-8 bytes, ensuring characters outside the ASCII range round-trip correctly.

When to Use Base64

Base64 is used whenever binary data needs to travel through a text-only channel. Common use cases include embedding images in CSS or HTML via data URIs, encoding authentication credentials in HTTP headers, transmitting binary payloads in JSON or XML, and encoding email attachments in MIME format. Because the output uses only safe ASCII characters, it avoids corruption from text-processing systems that might alter raw bytes.

Frequently Asked Questions

What is Base64 encoding?

Base64 is a binary-to-text encoding scheme that represents binary data as an ASCII string. It uses 64 characters (A-Z, a-z, 0-9, +, /) plus = for padding. It's commonly used to embed binary data in text-based formats like JSON, XML, HTML, and email.

Does this tool support Unicode and emoji?

Yes — the tool encodes text to UTF-8 first using the TextEncoder API, then Base64-encodes the resulting bytes. This means Unicode characters, accented letters, CJK characters, and emoji all encode and decode correctly.

Can I decode Base64 back to text?

Yes — the tool is bidirectional. Type or paste Base64 in the right panel and the decoded text appears instantly in the left panel.

Is this tool free?

Yes — completely free, forever. No sign-up, no account, no usage limits.

Is my data safe?

All encoding and decoding happens locally in your browser using JavaScript. Nothing is uploaded to any server. It's safe to use with sensitive or proprietary data.

Why does Base64 make strings longer?

Base64 encodes every 3 bytes of input into 4 ASCII characters, resulting in roughly 33% size overhead. This tradeoff is accepted because the output is guaranteed to be safe for text-based transport protocols.