Base64 Encode
Free Base64 Encoder Online
About Base64 Encode
Base64 Encode is a free, instant, browser-based tool that converts any text string or data to its Base64 encoded representation. Base64 encoding is a binary-to-text encoding scheme that represents binary or text data using only 64 printable ASCII characters (A-Z, a-z, 0-9, +, /, and = for padding), making data safe to transmit and store in systems that only support text.
Base64 encoding is deeply embedded in modern web development and internet protocols. It is used to encode image, font, and audio data for embedding directly in HTML or CSS as data URIs — eliminating additional HTTP requests. HTTP Basic Authentication requires credentials (username:password) to be Base64 encoded before being placed in the Authorization header. Email attachments are encoded using Base64 in MIME format before transmission through SMTP. TLS/SSL certificates (PEM format) use Base64 encoding. JSON Web Tokens (JWTs) encode their header and payload using Base64URL. Public and private keys in cryptography are commonly distributed in Base64-encoded PEM files.
The standard Base64 alphabet is defined in RFC 4648 §4. The URL-safe variant, defined in RFC 4648 §5, replaces the + character with - and the / character with _ to produce output that can be safely included in URLs and filenames without requiring percent-encoding. This tool supports both variants.
Base64 encoding is deeply embedded in modern web development and internet protocols. It is used to encode image, font, and audio data for embedding directly in HTML or CSS as data URIs — eliminating additional HTTP requests. HTTP Basic Authentication requires credentials (username:password) to be Base64 encoded before being placed in the Authorization header. Email attachments are encoded using Base64 in MIME format before transmission through SMTP. TLS/SSL certificates (PEM format) use Base64 encoding. JSON Web Tokens (JWTs) encode their header and payload using Base64URL. Public and private keys in cryptography are commonly distributed in Base64-encoded PEM files.
The standard Base64 alphabet is defined in RFC 4648 §4. The URL-safe variant, defined in RFC 4648 §5, replaces the + character with - and the / character with _ to produce output that can be safely included in URLs and filenames without requiring percent-encoding. This tool supports both variants.
starKey Features
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Standard Base64 Encoding
Encodes text and data using the standard RFC 4648 Base64 alphabet with correct = padding, fully compatible with all standard Base64 decoders in any programming language.
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URL-safe Base64 Variant
Optionally produces URL-safe Base64 (RFC 4648 §5) output which replaces + with - and / with _ — safe for use in URLs, HTTP headers, and filenames without percent-encoding.
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Full Unicode and UTF-8 Support
Correctly handles all Unicode characters including Chinese, Arabic, Japanese, emoji, and accented Latin characters by first encoding text to UTF-8 bytes before applying Base64.
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Real-time Encoding
Encodes your input in real time as you type, providing immediate Base64 output without needing to click a button — ideal for quickly encoding short strings.
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Browser-based and Private
All encoding happens entirely in your browser using JavaScript. Sensitive strings like passwords, API keys, and tokens never leave your device or reach any server.
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Instant Copy
Copy the Base64 encoded output to your clipboard with a single click for immediate use in Authorization headers, HTML data URIs, JWT creation, or configuration files.
help_outlineHow to Use
1
Enter Your Text or Data
Type or paste the text string you want to encode into the dark input textarea on the left side of the tool.
2
Click Process
Press the Process button or use Ctrl+Enter. The tool immediately converts your input text to its Base64 encoded representation.
3
Review the Encoded Output
The Base64 encoded string appears in the output area. Verify the length and format match what you expect for your use case.
4
Copy and Use
Click the Copy button to copy the Base64 string to your clipboard for use in your Authorization header, data URI, JWT library, or any other application.
lightbulbUse Cases
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Data URI Image Embedding
Encode image bytes as Base64 for embedding directly in HTML ![]()
src attributes or CSS background-image properties as data: URIs, eliminating separate image file HTTP requests.
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HTTP Basic Authentication
Encode username:password credentials to Base64 for the Authorization: Basic header used in HTTP Basic Authentication when making requests to APIs that require this scheme.
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Email Attachment Encoding
Encode binary file attachments to Base64 for inclusion in MIME-formatted email messages where all content must be represented as printable ASCII text.
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JWT Token Construction
Understand and generate the Base64URL-encoded header and payload sections of JSON Web Tokens for authentication system implementation and debugging.
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Embedding Binary in JSON or XML
Encode binary data (images, certificates, compiled files) as Base64 strings for safe embedding in JSON or XML documents that cannot contain raw binary bytes.