Encoders & Decoders

Base64 Encoder / Decoder

Encode text or files to Base64 or decode Base64 back to text. Supports image preview, data URL output, and one-click direction swap — nothing sent to a server.

Encode & Decode
Text & File Input
Data URL Output
Image Preview
Browser-only

Text to Encode

Enter text or a file above and click Encode / Decode

Base64 Encoding and Decoding

Base64 converts bytes into a safe text alphabet of 64 characters. It is useful when binary content must pass through JSON, HTML, CSS, email, or another text-only channel.

Common uses

Data URI images and fonts
MIME email attachments
Binary fields in JSON APIs
PEM certificates and keys
URL-safe token components

Base64 is not encryption. Anyone can reverse it, and encoded data is about one third larger than its original byte sequence.

const encoded = btoa("Hello");
const decoded = atob(encoded);

import base64
base64.b64encode(b"Hello").decode()

Unicode text must first become UTF-8 bytes. This tool handles that conversion automatically and keeps all processing local to your browser.

Frequently Asked Questions

What is Base64?: Base64 is an encoding scheme that converts binary data into a text representation using 64 characters (A-Z, a-z, 0-9, +, /). It is widely used to embed binary data like images in JSON, HTML, or email where binary data cannot be directly embedded.
Is Base64 encryption?: No. Base64 is an encoding scheme, not encryption. It does not provide any security or confidentiality - anyone can decode a Base64 string instantly. Do not use Base64 to protect sensitive data.
When should I use Base64?: Common uses include: embedding images as data URLs in HTML/CSS, encoding binary data for JSON APIs, encoding email attachments (MIME), and storing binary data in text-only formats like XML.
Is my data safe?: Yes. All encoding and decoding happens entirely in your browser using JavaScript's built-in btoa() and atob() functions. Your text and files are never sent to any server.
Why is Base64 output longer than the input?: Base64 encodes every 3 bytes of input as 4 characters, adding approximately 33% overhead. This is the trade-off for binary-safe text representation.
Can I encode images and files?: Yes. Use the File mode to upload any file. The tool reads it as a data URL and extracts the Base64 portion. You can use the output as a data URI directly in HTML: <img src="data:image/png;base64,...">

Disclaimer

This tool is provided for general informational and utility purposes only. Results may be inaccurate, incomplete, outdated, or contain errors. Always verify results before relying on or using them.

Some tools may use AI, automated processing, third-party services, or server-side processing. Do not rely on these tools as a substitute for professional advice.

Use at your own risk. BestToolOnline makes no guarantees regarding the accuracy, reliability, completeness, availability, or suitability of results, to the maximum extent permitted by applicable law.

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Base64 Encoding and Decoding

Base64 converts bytes into a safe text alphabet of 64 characters. It is useful when binary content must pass through JSON, HTML, CSS, email, or another text-only channel.

Common uses

Data URI images and fonts

MIME email attachments

Binary fields in JSON APIs

PEM certificates and keys

URL-safe token components

Base64 is not encryption. Anyone can reverse it, and encoded data is about one third larger than its original byte sequence.

const encoded = btoa("Hello"); const decoded = atob(encoded);

import base64 base64.b64encode(b"Hello").decode()

Unicode text must first become UTF-8 bytes. This tool handles that conversion automatically and keeps all processing local to your browser.

Frequently Asked Questions

What is Base64?

Base64 is an encoding scheme that converts binary data into a text representation using 64 characters (A-Z, a-z, 0-9, +, /). It is widely used to embed binary data like images in JSON, HTML, or email where binary data cannot be directly embedded.

Is Base64 encryption?

No. Base64 is an encoding scheme, not encryption. It does not provide any security or confidentiality - anyone can decode a Base64 string instantly. Do not use Base64 to protect sensitive data.

When should I use Base64?

Common uses include: embedding images as data URLs in HTML/CSS, encoding binary data for JSON APIs, encoding email attachments (MIME), and storing binary data in text-only formats like XML.

Is my data safe?

Yes. All encoding and decoding happens entirely in your browser using JavaScript's built-in btoa() and atob() functions. Your text and files are never sent to any server.

Why is Base64 output longer than the input?

Base64 encodes every 3 bytes of input as 4 characters, adding approximately 33% overhead. This is the trade-off for binary-safe text representation.

Can I encode images and files?

Yes. Use the File mode to upload any file. The tool reads it as a data URL and extracts the Base64 portion. You can use the output as a data URI directly in HTML: <img src="data:image/png;base64,...">

Disclaimer

Some tools may use AI, automated processing, third-party services, or server-side processing. Do not rely on these tools as a substitute for professional advice.