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Base64 Encoder & Decoder

Encode plain text to Base64 or decode any Base64 string back to human-readable text — instantly, securely, and entirely in your browser.

100% FreeNo Sign-upUnicode / UTF-8 SupportPrivacy First

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of printable ASCII characters. The name comes from the fact that it uses a 64-character alphabet — the 26 uppercase letters (A–Z), 26 lowercase letters (a–z), the 10 digits (0–9), plus + and /, with = used for padding.

The encoding works by splitting every 3 bytes of input data into 4 groups of 6 bits each. Each 6-bit group maps to one of the 64 characters in the alphabet. This means a Base64-encoded string is typically about 33% larger than the original binary data.

Base64 is defined in RFC 4648 and is widely used in web technologies, email systems, data URIs, and cryptographic protocols.

Common Use Cases for Base64

Embedding Images in HTML & CSS | WebUtilsFree

Base64 lets you inline images directly into HTML or CSS as Data URIs (e.g., src="data:image/png;base64,..."). This eliminates an extra HTTP request, which can speed up rendering of small icons and SVGs.

Email Attachments (MIME) | WebUtilsFree

The MIME email standard uses Base64 to encode binary attachments (images, PDFs, etc.) so they can be safely transported over email protocols that only handle 7-bit ASCII text.

HTTP Basic Authentication | WebUtilsFree

The HTTP Authorization header encodes credentials as Base64: the browser sends "Authorization: Basic <base64(username:password)>". Note that Base64 is encoding, not encryption — always use HTTPS.

JSON Web Tokens (JWT) | WebUtilsFree

JWTs use a URL-safe variant of Base64 (called Base64url) to encode the header and payload sections of the token, making them safe to transmit in URLs and cookies.

Storing Binary Data in Databases | WebUtilsFree

Databases that only support text fields (like some NoSQL stores or XML-based systems) can store binary data by Base64-encoding it first.

How to Use Our Base64 Tool

Our tool is designed to be instant and effortless — no account required, no data ever leaves your device:

  1. 1Paste your plain text or Base64 string into the left input panel.
  2. 2Click "Encode to Base64" to convert your plain text into a Base64 string, or "Decode from Base64" to convert a Base64 string back to plain text.
  3. 3If you decode an invalid string, a clear error message will appear explaining the problem — the app will never crash.
  4. 4Use "Swap" to move the output back into the input field for chained operations.
  5. 5Click "Copy Output" to copy the result to your clipboard instantly.

Base64 vs Encryption — What's the Difference?

This is one of the most common misconceptions about Base64. It is not encryption. Base64 is a reversible encoding — anyone who receives a Base64 string can immediately decode it with no key or password.

Base64 (Encoding)

  • ✓ Transforms binary data into text
  • ✓ Fully reversible by anyone
  • ✓ No key or secret required
  • ✗ Provides zero security/privacy

Encryption (e.g., AES-256)

  • ✓ Protects data with a cryptographic key
  • ✓ Only reversible with the correct key
  • ✓ Provides confidentiality and security
  • ✗ More complex to implement correctly