Base64 to hex Converter

A Base64 to Hex converter takes a Base64-encoded string and decodes it into its hexadecimal representation — a format where every byte of binary data is expressed as two hexadecimal digits (0–9, a–f). Rather than producing a file like the PDF converter does, it gives you a human-readable string of hex values that directly represent the underlying bytes.

Hex is the lingua franca of low-level data inspection. Developers and security professionals reach for hex when they need to see exactly what bytes are hiding inside an encoded payload. Common use cases include debugging API responses where you suspect encoding corruption, inspecting cryptographic data like hashes, signatures, keys, and certificates that often travel as Base64, analysing binary file headers to verify a file’s true type, and working with network protocols or embedded systems that express data in hex. Converting Base64 to hex essentially lifts the curtain — instead of an opaque string of letters and numbers, you see the raw byte values that make up the actual data.

Since the output is a text string rather than a binary file, large inputs can generate enormous hex strings very quickly. A 1 MB binary payload becomes roughly 1.33 MB of Base64, which then decodes to 2 MB of hex text (two characters per byte). The browser handles this purely in memory, so modest inputs — cryptographic keys, short binary blobs, encoded images, document headers — are no problem at all. For very large payloads the output string can become unwieldy to display and copy, and the visual chip mode in particular can slow the browser down since it renders a separate DOM element per byte. Plain or spaced output formats are far more efficient for large inputs.

The conversion happens in three stages. First, the Base64 string is normalised — whitespace is stripped so that line-wrapped or formatted strings are handled cleanly. Second, JavaScript’s atob() function decodes the Base64 into a binary string, where each character represents one byte of data. Third, every character in that binary string is passed through charCodeAt() to get its numeric byte value, which is then converted to a two-character hex string using toString(16) with zero-padding to ensure single-digit values like 5 are written as 05. The resulting hex values are then formatted according to whichever output mode you chose — spaced (48 65 6c), plain (48656c), 0x-prefixed (0x48 0x65), or rendered as colour-coded chips for visual inspection.

Completely. It’s a single HTML file that runs entirely in your browser with no account, no backend, no telemetry, and no cost. You can save it to your desktop and use it offline indefinitely.