Base64 Encoder

Encode text or binary data to Base64 format.

Text → Base64

Input

Output

Result will appear here…

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What Is Base64 Encoding?

Base64 is an encoding scheme that converts binary or text data into a safe string of 64 ASCII characters (A–Z, a–z, 0–9, +, /). It was designed to transmit data through systems that only handle plain text — like email, HTML attributes, URLs, and JSON payloads. Base64 is not encryption; it is purely an encoding format that can be reversed instantly.

Why Do You Need Base64?

Many systems in web development and data transfer require data to be in a plain-text format. Embedding an image directly in a CSS or HTML file, passing binary data in a JSON API, or storing a small file in a database field are all situations where Base64 is the standard solution. It is especially common in Basic Authentication HTTP headers, which encode the username and password as Base64 before transmission.

Common Use Cases

Email attachments — MIME protocol uses Base64 to encode file attachments so they survive email transmission
Inline images — Embed small icons directly in CSS as url("data:image/png;base64,…")
API authentication — HTTP Basic Auth sends Authorization: Basic dXNlcjpwYXNz
JSON payloads — Binary data (PDFs, images) stored inside JSON fields
URL-safe tokens — Encode tokens before placing them in query strings
Browser localStorage — Store binary content as text strings

How to Use the Base64 Encoder/Decoder

Encoding is simple: paste your plain text, click Encode, and copy the resulting Base64 string. Decoding works in reverse — paste a Base64 string, click Decode, and retrieve the original text. The Swap button lets you instantly flip directions and verify a round-trip encode-decode cycle to confirm accuracy.

Base64 vs. Encryption

A common misconception is that Base64 encoding provides security. It does not. Anyone who receives a Base64 string can decode it instantly with any Base64 tool. It is a reversible encoding format, not a cipher. For secure data transmission, always use proper encryption (AES, RSA) in addition to Base64 encoding when required.

Privacy Guarantee

All Base64 encoding and decoding happens entirely inside your browser. Your text never leaves your device and is never sent to any server. This makes the tool safe for encoding sensitive strings like API keys or tokens — as long as you are on a secure, private device.

Frequently Asked Questions

Is Base64 encoding the same as encryption?

No. Base64 is a reversible encoding scheme, not encryption. Anyone with a Base64 decoder can retrieve the original data immediately. Use actual encryption (AES-256, RSA) to protect sensitive data. Base64 is only for making binary data safe for text-based systems.

Why does the Base64 output end with "=" signs?

The equals sign (=) is padding. Base64 encodes 3 bytes of input into 4 characters. When the input length is not a multiple of 3, padding characters fill the remaining space to maintain consistent block sizes. One or two equals signs at the end are completely normal and expected.

Can I Base64 encode images or files?

This tool handles text encoding. To encode image files to Base64, you would need a tool that reads file bytes directly. However, if you paste the raw binary content of a file as text, the encoder will process it. For images, browser-based file readers are more reliable.

What is URL-safe Base64?

Standard Base64 uses + and / characters, which have special meanings in URLs. URL-safe Base64 replaces + with - and / with _, making the encoded string safe to include directly in a URL without percent-encoding. Always check which variant your system expects.

Why does my decoded text look garbled?

If the decoded output appears as strange characters, the original data was likely binary (an image, PDF, or executable) rather than plain text. Base64 can represent any binary data, but only text data will appear readable when decoded to a string. Binary content needs to be handled as a file, not a string.

Is there a size limit?

There is no enforced limit in this tool beyond what your browser can handle in memory. Base64 encoding increases file size by approximately 33% (every 3 bytes becomes 4 characters), so a 1 MB input becomes roughly 1.33 MB of Base64 output.

Does Base64 work for all languages and character sets?

Yes. This tool uses proper UTF-8 encoding before Base64 conversion, so it correctly handles Arabic, Chinese, Japanese, emoji, and all Unicode characters. The encoder first converts the text to UTF-8 bytes, then applies Base64, ensuring international characters round-trip correctly.

Is it free and private?

Completely free with no account required. All processing runs locally in your browser using the built-in btoa() and atob() JavaScript functions. No data is transmitted anywhere.