Base64 Encoder — Free, Instant & Online

Encode text or files to Base64 directly in your browser. Supports URL-safe encoding, line-by-line mode, and real-time live encoding. Nothing is uploaded — all processing happens on your device.

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Drag & drop a file here or

Any file type — images, documents, etc.

How to Encode Text to Base64

  1. Paste or type your text — Enter any text into the input field. With Live mode on, encoding happens instantly as you type.
  2. Choose your options — Enable URL-safe encoding for use in URLs and JWT tokens. Use line-by-line mode to encode multiple values at once.
  3. Copy or download — Copy the Base64 output to your clipboard or download it as a .txt file.

How to Encode a File to Base64

  1. Switch to the File tab — Click the File tab above the tool.
  2. Upload your file — Drag and drop any file (image, PDF, document, audio) onto the upload zone or click to browse.
  3. Choose output format — Toggle the data URI prefix option on to get a ready-to-use data:image/png;base64,... string for embedding in HTML/CSS, or off for the raw Base64 string.
  4. Copy or download — Copy the output or save it as a .txt file.

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that converts any data — text, images, files — into a safe sequence of 64 printable ASCII characters. The name comes from the 64 characters used: A–Z, a–z, 0–9, plus (+), and forward slash (/), with equals (=) for padding.

Base64 doesn’t compress or encrypt your data. It represents it in a different format that can safely travel through systems that only support ASCII text — like email protocols, JSON APIs, and HTML attributes.

Common Uses for Base64 Encoding

  • Data URIs — Embed images directly in HTML or CSS without separate file requests: <img src="data:image/png;base64,...">
  • Email attachments — MIME encoding uses Base64 to transmit binary attachments through text-based email protocols
  • HTTP Basic Auth — Credentials are Base64-encoded in Authorization headers: Authorization: Basic dXNlcjpwYXNz
  • JWT tokens — JSON Web Tokens use URL-safe Base64 to encode header and payload sections
  • API payloads — Binary data embedded in JSON, XML, or other text-based formats
  • Configuration files — Encoding secrets and keys for environment variables

URL-Safe Base64 vs Standard Base64

Standard Base64 uses + and / characters which are reserved in URLs and query strings. URL-safe Base64 (Base64URL) replaces + with - and / with _, making the output safe to use directly in URLs without percent-encoding. Use URL-safe mode when generating tokens, encoding URL parameters, or working with JWT tokens.

FAQ

Frequently Asked Questions

Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of printable ASCII characters. It represents binary data using 64 characters: A-Z, a-z, 0-9, plus (+), and forward slash (/), with equals (=) used for padding. Base64 is widely used to embed images in HTML/CSS, transmit binary data through text-based protocols like email (MIME), and store complex data in JSON or XML formats.

Common use cases include: embedding images directly in HTML or CSS using data URIs, sending binary attachments through email (MIME encoding), storing binary data in JSON or XML documents, encoding authentication credentials for HTTP Basic Auth headers, transmitting data through URLs or query parameters that only support ASCII characters, and encoding configuration data or tokens in web applications.

Standard Base64 uses the characters + and / which have special meanings in URLs. URL-safe Base64 (also called Base64URL) replaces + with - (hyphen) and / with _ (underscore), making the output safe to use directly in URLs, filenames, and query parameters without additional percent-encoding. This variant is commonly used in JWT (JSON Web Tokens), OAuth tokens, and URL parameters.

No. Base64 is an encoding scheme, not an encryption method. Anyone can decode Base64 text back to its original form — there is no secret key or password involved. Base64 is designed for data representation and transport, not security. If you need to protect sensitive data, use proper encryption (AES, RSA, etc.) before Base64 encoding the encrypted output.

Base64 encoding increases data size by approximately 33%. Every 3 bytes of input data becomes 4 bytes of Base64 output. For example, a 1MB file becomes roughly 1.33MB when Base64 encoded. This overhead is the trade-off for being able to represent binary data as safe ASCII text. Keep this size increase in mind when embedding large files as data URIs.

Yes. Switch to the File tab, drag and drop any file (images, PDFs, documents, audio, video, etc.), and the tool will output its Base64 representation. With the "Include data URI prefix" option enabled, the output includes the correct MIME type header (e.g., data:image/png;base64,...) ready to paste directly into HTML img tags or CSS background-image properties.

When enabled, each line of your input text is encoded independently, producing one Base64 string per line. This is useful when you have a list of values (API keys, tokens, passwords, usernames) that you need to encode individually in bulk, rather than encoding the entire multi-line text as a single Base64 string.

No. All encoding happens entirely in your browser using JavaScript. Your text and files never leave your device — nothing is uploaded, stored, or transmitted to any server. This makes the tool completely safe for encoding sensitive data like API keys, passwords, authentication tokens, or confidential documents.

There is no enforced limit — all processing happens locally in your browser. However, extremely large inputs (over 50MB) may cause your browser to slow down or run out of memory depending on your device. For typical use cases like encoding text, images, or documents, the tool handles files of any practical size without issues.

Yes, completely free. No account required, no sign-up, no usage limits, no ads interrupting your workflow. Since all processing happens client-side in your browser, there are no server costs to cover.