When would I need to convert decimal to hex?

Common use cases include computing colour values (CSS #RRGGBB), working with memory addresses, encoding byte values in protocols, and debugging binary data.

Is the hex output uppercase or lowercase?

Always uppercase, for example FF rather than ff.

Can I convert a negative decimal to hex?

Type a minus sign first and the hex row shows the same magnitude with a minus sign, so -255 becomes -FF. The converter does not produce two's complement values such as FFFFFF01.

How do I convert decimal to hex by hand?

Divide by 16 repeatedly and write the remainders from last to first, using A to F for 10 to 15. 419 leaves 3, 10 (A) and 1, so it is 1A3.

Decimal to hex converter

Enter a decimal number (base 10) to instantly see its hexadecimal, binary, and octal equivalents. Output is shown in uppercase hex.

DEC input (base 10)

BIN–

OCT–

DEC–

HEX–

INPUT BASE

All bases shown simultaneously.

Runs entirely in your browser

Worked example

Divide by 16 and keep the remainders: 419 ÷ 16 = 26 r 3, 26 ÷ 16 = 1 r 10 (A), 1 ÷ 16 = 0 r 1. Read them from last to first: 1A3.

How it works

The input is checked digit by digit and turned into a JavaScript BigInt, then written out with BigInt.prototype.toString(base), so large values stay exact. All four bases are computed simultaneously from the same input value, so you can see binary, octal, decimal, and hex at a glance.

Processing runs in your browser

All conversion runs in your browser tab. Our servers are not involved at any point.

Related operations

For converting between data sizes like KB and MB, try the byte converter. To compute MD5 or SHA hashes from values, use the hash generator. For working with file permission bits, see the chmod calculator.

Frequently asked questions

When would I need to convert decimal to hex?: Common use cases include computing colour values (CSS #RRGGBB), working with memory addresses, encoding byte values in protocols, and debugging binary data.
Is the hex output uppercase or lowercase?: Always uppercase, for example FF rather than ff.
Can I convert a negative decimal to hex?: Type a minus sign first and the hex row shows the same magnitude with a minus sign, so -255 becomes -FF. The converter does not produce two's complement values such as FFFFFF01.
How do I convert decimal to hex by hand?: Divide by 16 repeatedly and write the remainders from last to first, using A to F for 10 to 15. 419 leaves 3, 10 (A) and 1, so it is 1A3.

Last reviewed September 30, 2026

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