Crypto Tools
What It Does
Encodes text/binary data to Base64 or decodes Base64 back to the original content.
How to Use It
- Paste your text (to encode) or a Base64 string (to decode).
- Select “Encode” or “Decode”.
- The result appears in the output area.
Options Explained
| Option | Description |
|---|---|
| Mode | Encode (text → Base64) or Decode (Base64 → text) |
| URL-safe | Use Base64url variant (- and _ instead of + and /) |
| Remove padding | Strip trailing = characters from encoded output |
Example
Input: Hello, World! → Encode → SGVsbG8sIFdvcmxkIQ==
About Base64 Encoding
Base64 is a binary-to-text encoding scheme that represents binary data using a set of 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It was originally designed for safely transmitting binary content over text-only channels such as email (MIME) and early HTTP. The encoding increases data size by approximately 33%, since every three bytes of input produce four characters of output.
Several Base64 variants exist for different contexts. Standard Base64 (RFC 4648) uses + and / with = padding. URL-safe Base64 replaces those with - and _ to avoid conflicts in URLs and filenames. Some implementations omit padding entirely when the length is known. This tool automatically handles both variants and padding options.
It is important to understand that Base64 is an encoding, not encryption. It provides no confidentiality — anyone can decode a Base64 string. For protecting sensitive data, use proper encryption algorithms such as AES-GCM.
Common Use Cases
- Embedding images and fonts as data URIs in HTML and CSS
- Encoding binary attachments in email (MIME) messages
- Transmitting binary data in JSON and XML payloads
- Encoding cryptographic keys, certificates, and tokens (PEM, JWTs)
- Storing small binary blobs in text-based configuration files
- Passing binary parameters through URL query strings (URL-safe variant)
What Is Base64?
Base64 is a binary-to-text encoding scheme that represents binary data using a set of 64 printable ASCII characters (A–Z, a–z, 0–9, +, and /). It was originally defined in RFC 4648 and is fundamental to standards like MIME (email attachments), PEM (cryptographic certificates), and data URIs in HTML. Because Base64 uses only characters that are safe in text-based protocols, it allows binary content such as images, keys, and compressed data to travel through systems that only support plain text. A URL-safe variant replaces + and / with - and _ to avoid encoding issues in URLs and filenames.
Frequently Asked Questions
Is Base64 a form of encryption?
No. Base64 is an encoding, not encryption. It is fully reversible by anyone without a key. Never use Base64 to protect sensitive data — use authenticated encryption like AES-GCM instead.
Why does Base64 increase the data size?
Base64 represents every 3 bytes of input as 4 ASCII characters, resulting in roughly a 33% size increase. This overhead is the trade-off for safe transport through text-only channels.
What is the difference between standard and URL-safe Base64?
Standard Base64 uses + and / as the 62nd and 63rd characters. URL-safe Base64 (RFC 4648 §5) replaces them with - and _ so the output can be used directly in URLs and filenames without percent-encoding.
Is my data sent to a server?
No. All encoding and decoding happens locally in your browser. Your data is never transmitted or stored.
All encoding and decoding runs entirely in your browser. No data is sent to any server, ensuring your content remains private.