Base64 Encoder / Decoder
Encode or decode Base64 strings.
What is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 ASCII characters (A-Z, a-z, 0-9, +, /). It was designed to safely transmit binary data through systems that only support text, such as email (MIME) and HTML/CSS (data URIs). Every 3 bytes of input become 4 characters of output, making encoded data roughly 33% larger.
How to Use
- Paste text or a Base64 string into the input field.
- Click Encode to convert plain text to Base64, or Decode to convert Base64 back to text.
- Copy the output for use in your code, emails, or data URIs.
Frequently Asked Questions
Is Base64 encryption?
No. Base64 is an encoding, not encryption. It provides no security-anyone can decode it. It's only meant to make binary data safe for text-based transport. If you need to protect sensitive data, use proper encryption (like AES) before optionally Base64-encoding the encrypted output for transport.
What are common uses for Base64?
Embedding images in CSS/HTML as data URIs, encoding email attachments (MIME), passing binary data in JSON APIs, and storing small files in databases as text. For example, a small icon can be inlined as a data URI to avoid an extra HTTP request. JWT tokens also use Base64url encoding for their header and payload sections.
Why does Base64 make data larger?
Because it encodes 3 bytes into 4 ASCII characters, the output is always about 33% larger than the input. This is the trade-off for text-safe representation. For example, a 30KB image becomes roughly 40KB when Base64 encoded. For large files, this overhead makes Base64 impractical-binary transfer is preferred when the transport supports it.
