Binary, Hex, Decimal & Octal Converter
Convert instantly between binary, octal, decimal, and hexadecimal as you type. Free to use, no signup required for occasional use.
What is the Binary / Hex / Decimal / Octal Converter?
The Binary / Hex / Decimal / Octal Converter instantly converts a number between the four number systems developers and students work with most: binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Different contexts favor different bases — binary maps directly onto how computers store data at the hardware level, hexadecimal is the compact, human-friendly way of representing binary values in code, memory addresses, and color codes, octal shows up in older Unix file permission notation, and decimal is how humans normally think about numbers day to day. Manually converting between these bases by hand is slow and error-prone, especially for larger values, so this tool lets you type a number into any one of the four fields and see the equivalent value update instantly and correctly in the other three, with input validation that only accepts valid digits for whichever base you're typing in (for example, rejecting '9' as invalid input while typing in binary or octal). It's a handy everyday utility for programmers debugging low-level code, students learning number systems, and anyone working with file permissions, color codes, or memory addresses.
How to use it
Click into any one of the four input fields — binary, octal, decimal, or hexadecimal — and start typing your number. As you type, the tool validates that you're only entering valid digits for that base (so, for example, the binary field only accepts 0 and 1), and instantly recalculates and displays the equivalent value in the other three fields in real time, with no need to click a convert button. To start a new conversion, clear the field you were typing in, or click into a different field and enter a new value there instead. If you enter an invalid character for the selected base, the tool will flag it so you can correct your input before the conversion updates. This makes it quick to jump between bases when reading hex color codes, checking file permission octal values, or verifying binary representations of small integers.
Frequently asked questions
Does the conversion happen automatically as I type, or do I need to click a button?
Conversion happens automatically and instantly as you type in any of the four fields — no button click is required.
What happens if I type an invalid character for a base, like an '8' in binary?
The tool validates input against the allowed digits for each base and will flag or reject characters that aren't valid in that number system, so you can correct your entry.
Can this handle very large numbers?
Yes, the converter uses arbitrary-precision integer arithmetic under the hood, so it can accurately convert very large numbers well beyond typical 32-bit or 64-bit integer limits.
Does this support negative numbers or decimals?
This converter is built for non-negative whole numbers across all four bases, which covers the vast majority of everyday use cases like memory addresses, color codes, and file permissions.