URL Encoder / Decoder
Encode and decode URL components with percent-encoding instantly.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to plain text, right in your browser. Built for developers, designers, and anyone who works with data URIs, email attachments, or API payloads and needs a fast, private conversion tool that supports full UTF-8 characters.
How to Use This Tool
- Choose a mode — click "Encode" to convert plain text into Base64, or "Decode" to convert a Base64 string back to readable text.
- Type or paste your content into the input area. The output updates automatically as you type, so there is no submit button to press.
- Review the output — the converted result appears below the input. If the input is not valid Base64 while in decode mode, an error message will appear.
- Copy — click the "Copy" button to send the converted output straight to your clipboard.
- Clear — click "Clear" to reset both fields and start a new conversion.
What is Base64?
Base64 is a binary-to-text encoding scheme that represents arbitrary binary data using a set of 64 printable ASCII characters (A-Z, a-z, 0-9, +, and /). It works by taking every three bytes of input, splitting them into four 6-bit groups, and mapping each group to one of the 64 characters in its alphabet. When the input length is not evenly divisible by three, one or two padding characters (=) are appended to the output so that decoders know where the data ends.
The encoding was originally designed for transmitting binary content over channels that only support text, such as email via the MIME standard. Today it is used extensively across the web: data URIs embed images or fonts directly in HTML and CSS, JSON Web Tokens (JWTs) encode their header and payload as Base64URL strings, and many REST APIs accept file uploads as Base64-encoded fields within a JSON body.
Because Base64 maps three bytes to four characters, it increases the size of data by approximately 33%. It is important to understand that Base64 is an encoding, not encryption. The transformation is fully reversible without any secret key, so it should never be used to protect sensitive information. Its purpose is purely to ensure that binary data can safely pass through text-based systems without corruption.
Frequently Asked Questions
What is Base64 used for?
Base64 is used whenever binary data needs to travel through a text-only channel. The most common use cases include embedding images directly in HTML or CSS via data URIs, encoding email attachments in MIME format, transmitting binary payloads inside JSON or XML APIs, and encoding the header and payload sections of JSON Web Tokens (JWTs). It is also frequently used in configuration files and environment variables to safely store binary values as plain text strings.
Does Base64 encoding encrypt my data?
No. Base64 is an encoding scheme, not an encryption algorithm. It transforms data into a different textual representation but does not protect it with a secret key. Anyone with access to the Base64 string can decode it back to the original content instantly. If you need to protect sensitive information, apply a proper encryption method such as AES or RSA before encoding the result as Base64.
Why does Base64 increase the size of data?
Base64 represents every three bytes of input as four ASCII characters, resulting in roughly a 33% size increase. This happens because each output character carries only 6 bits of information (enough to index 64 symbols), so 24 bits of input (3 bytes) require 32 bits of output (4 characters). Padding characters (=) are added when the input length is not a multiple of three, ensuring that the encoded string length is always a multiple of four.
Is Base64 encryption?
No. Base64 is an encoding scheme, not encryption. It converts binary data into a text-safe format using a publicly known algorithm, and anyone can decode it without a key. It provides no confidentiality or security. If you need to protect data, apply proper encryption such as AES or RSA before Base64-encoding the result.
Why does Base64 increase file size?
Base64 maps every 3 bytes of input to 4 ASCII characters, because each character carries only 6 bits of information instead of 8. This means the output is always approximately 33% larger than the input. Additional padding characters (=) may be appended when the input length is not a multiple of three, adding slightly more overhead.
What is Base64URL encoding?
Base64URL is a variant of Base64 that replaces the + and / characters with - and _ respectively, and typically omits padding (=). This makes the output safe to use directly in URLs and filenames without additional percent-encoding. It is the encoding used in JSON Web Tokens (JWTs) and many modern web APIs.
When should I use Base64 encoding?
Use Base64 when you need to transmit binary data through a text-only channel. Common scenarios include embedding small images in HTML or CSS as data URIs, sending file attachments in email via MIME, including binary payloads in JSON or XML APIs, and encoding JWT header and payload sections. Avoid Base64 for large files where the 33% size overhead would be significant.