Base64 Encoding & Decoding – Free Tool for Strings, Files, and Images
A free online tool to quickly encode or decode strings and files into Base64 format.
Supports not only text input but also image files, with full compatibility for both UTF-8 and EUC-KR encoding.
Base64 is an essential standard for web development and data processing, used in email attachments, data URIs, and image conversion.
By converting an image to Base64, you can embed it directly into an HTML <img> tag and display it on the web without external files.
Have questions?
Check the FAQ.
Base64 encoding is a standard method for safely converting binary data such as images, files, and audio into text.
Since even unreadable data is expressed only with letters and numbers, it can be transmitted reliably across web browsers, servers, and email clients without breaking.
It is mainly used in email attachments, API communication, JSON/XML data handling, and image → data URI conversion, and it also ensures safe transfer of data containing multilingual characters or special symbols.
For example, web developers can convert an image into a Base64 string and embed it directly in an HTML <img> tag.
However, Base64 increases file size by about 33%, so it is optimized more for text-based data processing and web transmission than for large files.
In short, when data security and compatibility matter, Base64 encoding is an essential technology.
In most cases, an empty Base64 result is caused by a charset mismatch.
If the input data does not match the selected charset (UTF-8, EUC-KR, Shift-JIS, etc.), Korean, Japanese, emojis, or special characters may fail to convert and appear blank.
After checking that the correct charset is selected, you should also verify whether the data contains spaces, invalid characters, or incomplete strings.
For long text or binary data, using the file upload option ensures more stable results.
Most Base64 errors come from incorrect encoding settings or incomplete input. Reviewing the charset and cleaning up the data before conversion usually resolves the issue.
Base64 encoding is now an international standard for safely converting binary data into text across email, web, APIs, and file uploads.
But its origins trace back to early efforts to solve bit-level incompatibilities between computer systems.
In the 1970s–80s, systems processed data differently—8-bit, 7-bit, 6-bit—leading to frequent transmission errors and data loss.
Early email servers supported only text, so images, videos, and compressed files required a new encoding method.
Among various proposals, Base64 was chosen for its simplicity and efficiency, and was first formally defined in 1987 in the PEM (Privacy Enhanced Mail) protocol.
Later it was adopted into the MIME email standard, driving its widespread use. With the growth of the web and networking, Base64 became essential for data URIs, JSON, XML, cookies, and API communication.
Today Base64 remains a global standard under IETF RFC 4648 and is recognized as the leading solution for binary-to-text conversion across development environments worldwide.
Base64 encoding is designed to safely transmit and store binary data in text-based environments and is widely applied today in web development, email, APIs, and databases.
Common use cases include:
- Email attachments — Convert binary data such as images, documents, and audio into text for safe transfer (MIME standard).
- Web development (HTML/CSS) — Embed images directly into code via
data URIwithout external requests. - API communication — Encode binary data as Base64 strings in JSON or XML responses for reliable delivery.
- Security/cryptography — Convert encryption and hash results (binary values) into text for storage and sharing.
- Database management — Store binary data in text fields instead of BLOBs to improve portability and searchability.
Base64 solves character set compatibility issues, reduces transmission errors, and ensures portability and reliability across platforms—making it a core tool for web developers, server engineers, and data analysts.
Base64 encoding is not encryption. It is simply a way to represent binary data as text and does not provide any security features. Therefore, it should never be used to protect sensitive data such as passwords, personal information, or authentication tokens.
Because anyone can easily decode Base64 back to its original form, confusing it with encryption or hashing can lead to serious security risks.
✔️ Key differences
- Encoding: Data representation conversion (always reversible) → Base64.
- Encryption: Cannot be decrypted without a key. (For security)
- Hashing: One-way transformation, original cannot be restored. (For verification)
In practice, Base64 is often used to safely transmit the results of encryption or hashing (binary data) as text. However, using Base64 itself as protection for sensitive data is highly unsafe. Always use proper algorithms such as AES or RSA.
Base64 encoding is a way to safely convert binary data into text.
However, because the data is split into 6-bit units and represented using letters, numbers, and symbols (64 characters in total), the size grows by about 33% compared to the original.
📌 Example:
- Original image: 1MB (1024KB)
- After Base64 conversion: ~1.33MB
Therefore, while Base64 is useful for sending binary data safely in text-based environments such as email, JSON, XML, and APIs,
using it on large files can increase storage needs and waste bandwidth, causing performance issues.
Whenever possible, consider BLOB transfer or file attachments for efficiency.