Decimal to Hexadecimal
Convert a whole number from decimal (base-10) to hexadecimal (base-16).
About the Decimal to Hexadecimal converter
This tool converts a whole number from everyday base-10 into hexadecimal, the base-16 notation used throughout computing. Hex uses the digits 0 to 9 and the letters A to F, so 255 becomes FF and 4096 becomes 1000. It is the go-to format for colour codes, memory addresses, byte values, and permission masks.
How to use it
- Enter a decimal whole number in the input.
- The equivalent hexadecimal value appears immediately.
- Copy the hex result to use in CSS, code, or a hardware register.
A typical use is turning a colour value like 16711680 into the hex FF0000 used in web design. The converter handles very large values exactly rather than rounding, which matters when you work with 64-bit identifiers or long hashes. It expects whole numbers, not fractions. Everything is computed in your browser, so the numbers you enter never leave your device.
Frequently asked questions
What hex digits are used and what do the letters mean?
Hexadecimal uses 0-9 plus A-F, where A is 10, B is 11, and so on up to F which is 15. Two hex digits represent one byte, with a range of 00 to FF.
Does it handle very large numbers accurately?
Yes. The conversion uses exact integer arithmetic, so even 64-bit values and longer numbers convert without rounding errors.
Should I add a 0x prefix to the result?
The tool returns the raw hex digits. Many languages write hex with a 0x prefix (such as 0xFF), so add it yourself if your context requires it.
Can I convert decimal fractions to hex?
This converter is built for whole numbers. Fractional values are not supported, so round or truncate to an integer first.