π Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text. Instant, client-side.
How to Use This Tool
Select Encode or Decode mode, then type or paste your content. The output updates instantly. Use the Swap button to flip your encoded result back into the input for a round-trip test.
Choose Encode to convert plain text to Base64, or Decode to reverse a Base64 string.
Paste or type your input. The conversion happens automatically as you type.
Copy the output using the Copy Output button.
Use Swap to move the output back to input for chaining operations.
Base64 Encoding: What It Does and What It Does Not Do
Base64 takes binary or text data and maps every 3 bytes of input to 4 printable ASCII characters drawn from the set A-Z, a-z, 0-9, +, and /. If the input is not divisible by 3, padding characters (=) fill the end. The result is about 33% larger than the original. That size cost is acceptable when you need binary data to travel safely through text-only channels such as email (MIME), JSON payloads, or HTML attributes. One thing Base64 is not: encryption. Anyone with the string can decode it in seconds, so never use it to protect passwords or sensitive content. A separate but related format, Base64url, replaces + with - and / with _ so the output is safe to drop directly into a URL without percent-encoding. JWT tokens use Base64url for their header and payload sections, which is why you can paste a JWT here and decode the first two dot-separated segments to read the claims. The third segment (the signature) is cryptographic and cannot be decoded to plain text this way.
Common Use Cases
Frequently Asked Questions
What is Base64?
Base64 is an encoding scheme that converts binary data to ASCII text using 64 characters (A-Z, a-z, 0-9, +, /). It's used to transmit binary data over text-based protocols.
Is Base64 encryption?
No! Base64 is encoding, not encryption. It's easily reversible and provides no security. Don't use it to hide sensitive data.
Why use Base64?
To embed images in HTML/CSS (data URIs), encode binary data in JSON/XML, transmit data in email attachments (MIME), and encode credentials in HTTP Basic Auth.
What is the size increase?
Base64 encoding increases data size by approximately 33% (every 3 bytes become 4 characters).
What is URL-safe Base64?
Standard Base64 uses + and / which are special in URLs. URL-safe Base64 replaces + with - and / with _.