Base64 Encoder
Encode text to Base64 instantly in your browser with full UTF-8 Unicode support.
How Does Base64 Encoding Work?
Base64 is a binary-to-text encoding scheme that translates arbitrary sequences of 8-bit bytes into a set of 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It packs 24 bits of binary data (three 8-bit bytes) into four 6-bit chunks. When the input length is not a multiple of 3, the output is padded with one or two equals signs (=).
Mathematical 33% Expansion Rule:
Output Length = Math.ceil(Input Bytes / 3) * 4. A 30 KB file becomes ~40 KB in Base64 representation.
Complete UTF-8 & Unicode Support
Standard legacy JavaScript tools often use naive conversions like btoa(unescape(encodeURIComponent(str))), which fail or degrade performance on modern international characters. Our encoder uses the modern W3C TextEncoder API to properly translate multi-byte characters (Arabic, Urdu, Hindi, Chinese, Japanese, emoji) into strict UTF-8 bytes before radix-64 encoding.
Common Use Cases for Base64 Encoding
The HTTP Authorization: Basic <credentials> header requires username and password formatted as user:password and encoded in Base64.
Embedding small images, SVG vectors, or fonts directly inside HTML and CSS using data:image/png;base64,... to reduce HTTP request counts.
Tokens passed in cookies or URLs encode cryptographic header and claim JSON blocks using Base64URL to ensure compatibility across query strings.
SMTP was designed for 7-bit ASCII. Base64 encodes binary file attachments and rich multipart messages safely across email gateways.
Need to decode Base64 back to text?
Convert any Base64 string back into clean readable text in seconds.
Base64 Encoder FAQs
Detailed answers to common questions about Base64 encoding.
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