Base64 Encoder

Base64 encoding converts binary or text data into a string of printable ASCII characters using a 64-character alphabet (A-Z, a-z, 0-9, +, /) plus = for padding. This Base64 encoder lets you convert text to Base64 online — paste any string and get the encoded output instantly, entirely in your browser.

Base64 exists because many protocols and formats are designed to carry text, not raw bytes. Email (MIME), JSON, XML, HTML attributes, and HTTP headers can all corrupt or reject binary data. By encoding binary content into a safe ASCII subset, Base64 ensures data survives transport through these text-only channels without modification or loss.

Common uses of Base64 encoding include embedding images in HTML and CSS via data URIs, constructing HTTP Basic Authentication headers, encoding cryptographic keys and certificates in PEM format, building JWT token segments, and packaging binary payloads for REST APIs. The trade-off is size: Base64 encoding increases data by approximately 33% — every 3 input bytes become 4 Base64 characters. It is important to remember that Base64 is an encoding scheme, not encryption; anyone can decode a Base64 string, so it provides no confidentiality.

This Base64 encoding tool fully supports UTF-8 input, including accented characters, CJK text, and emoji. The text is first serialized to UTF-8 bytes and then Base64-encoded, matching the behavior of modern browsers and server runtimes. For the reverse operation, use our Base64 Decode tool, and to understand how Base64 fits into the broader encoding landscape, read our guide on Base64 Encoding Explained.