Base64 Encoder Online

Encode text and binary data to Base64 format — instant, private, browser-based

What Is Base64 Encoding?

Base64 encoding converts binary data or text into an ASCII string representation using a set of 64 printable characters (A-Z, a-z, 0-9, +, and /). This encoding is necessary when binary data needs to be transmitted through systems designed for text only — such as email (MIME), JSON payloads, XML documents, HTML data URIs, and URL parameters. The encoded output is roughly 33% larger than the original data.

Base64 is not encryption — it provides no security. It is purely a data encoding scheme that ensures binary content survives transport through text-based protocols without corruption. Every programming language provides Base64 encoding and decoding functions, and the format is standardized in RFC 4648. Common uses include embedding images in CSS or HTML, encoding authentication credentials in HTTP headers (Basic Auth), and transmitting file attachments in API requests.

How to Base64 Encode Text Online

1. Paste your text or binary content into the input field
2. Select the character encoding (UTF-8 is the default and most common)
3. Click Encode to convert the input to Base64
4. Copy the Base64 string from the output panel
5. Use the encoded string in your data URIs, API payloads, or email content

Why Use PinusX for Base64 Encoding?

PinusX encodes your data with 100% client-side processing — your text and files never leave your browser. This is essential because Base64 encoding is frequently used with sensitive data: HTTP Basic Authentication credentials (username:password), API tokens embedded in headers, private keys for JWT signing, and binary files containing proprietary content. In November 2025, jsonformatter.org leaked over 80,000 user credentials processed through their servers. PinusX eliminates this risk entirely by performing all encoding locally in your browser tab using JavaScript. No data is transmitted, stored, or logged on any server.

Frequently Asked Questions

Is Base64 encoding the same as encryption?

No. Base64 is an encoding scheme, not encryption. Anyone can decode Base64 back to the original data without a key. It provides zero security. If you need to protect data, use proper encryption (AES, RSA) before optionally Base64-encoding the encrypted result for transport.

Why does Base64 output become larger?

Base64 represents 3 bytes of binary data using 4 ASCII characters, resulting in approximately 33% size increase. This overhead is the trade-off for ensuring binary data can safely pass through text-only transport channels without corruption.

What is the difference between Base64 and Base64URL?

Standard Base64 uses + and / characters, which have special meaning in URLs. Base64URL replaces + with - and / with _ to make the encoded string URL-safe without requiring additional percent-encoding. Use Base64URL when the encoded data will appear in URLs or filenames.

Can I Base64 encode files and images?

Yes. Our tool supports file encoding — select a file from your device and it will be read and encoded entirely in your browser. The resulting Base64 string can be used as a data URI in HTML img tags, CSS background properties, or embedded in JSON payloads for API transmission.

What character encoding should I use?

UTF-8 is the standard and recommended encoding for most use cases. It handles all Unicode characters including emoji, CJK characters, and special symbols. Only use other encodings (ASCII, Latin-1) if you specifically need compatibility with legacy systems that expect those encodings.

Your data never leaves your browser. 100% client-side processing.