Decimal to Hex Converter
Type a whole number to see it in hex, worked out by dividing by 16 and turning the remainders 10–15 into A–F.
Decimal uses only the digits 0–9
In hex (base 16)
FF
Decimal 255 is FF in hex (base 16).
15×16 + 15 = 255
Tap a digit to step it up. Each tile is worth its digit × 16n.
How this works: Method, 1 source, Checked against 1 worked example,
How this works
Method
Divide the number by 16 and keep the remainder, a value from 0 to 15. Write remainders of 10 to 15 as the letters A to F. Keep dividing the quotient by 16 until it reaches 0, then read the remainders from last to first. Full method
How it’s tested
One worked example for this page is checked by automated tests before every release: given the inputs, the tool must show the expected answer.
Privacy
On your device. Nothing you enter or open leaves this browser. About privacy labels
Changes
- Rebuilt with 18 conversion pages, including text to binary and hex, two’s complement, IEEE 754 floating point, a bitwise calculator and Roman numerals, each with its method and a table.
- Added key facts with worked examples of converting between bases.
- Redesigned: the working shown step by step, and the same number in the other common bases under the answer.
- Fixed large numbers: values above 2^53, such as 64-bit hex, now convert exactly instead of rounding.
- First published.
How to convert decimal to hex
Divide the number by 16 and keep the remainder, a value from 0 to 15. Write remainders of 10 to 15 as the letters A to F. Keep dividing the quotient by 16 until it reaches 0, then read the remainders from last to first.
For 48,879: 48,879 ÷ 16 = 3,054 r 15 (F), 3,054 ÷ 16 = 190 r 14 (E), 190 ÷ 16 = 11 r 14 (E), 11 ÷ 16 = 0 r 11 (B). Reading upward gives BEEF, a value programmers like to use as a recognisable marker.
Another route is through binary: write the number in binary, then group the bits in fours from the right. Each group of four is one hex digit.
n = 16 × q + r, with r from 0 to 15 written 0–9, A–F
- Web colours are hex: #RRGGBB gives red, green and blue one byte each, 00 to FF (0 to 255), so 255 128 0 is #FF8000. Source: CSS Color Module Level 4, hex notation.
Round decimal numbers in hex
Decimal values that come up in code, colours and memory sizes, with their hex form.
| Decimal | Hex | Where you see it |
|---|---|---|
| 10 | A | |
| 15 | F | largest single hex digit |
| 16 | 10 | |
| 32 | 20 | ASCII space |
| 64 | 40 | |
| 100 | 64 | |
| 127 | 7F | largest signed byte |
| 128 | 80 | |
| 200 | C8 | |
| 255 | FF | largest byte, a full colour channel |
Show all 20 rowsShow fewer
| 256 | 100 | |
| 1,000 | 3E8 | |
| 1,024 | 400 | 1 KiB |
| 4,096 | 1000 | a common memory page (4 KiB) |
| 10,000 | 2710 | |
| 48,879 | BEEF | the BEEF marker |
| 65,535 | FFFF | largest 16-bit value, highest TCP port |
| 1,000,000 | F4240 | |
| 16,777,215 | FFFFFF | white, #FFFFFF |
| 4,294,967,295 | FFFFFFFF | largest 32-bit value |
Frequently Asked Questions
What is 255 in hex?
255 is FF: 255 ÷ 16 = 15 r 15, and 15 is F, so both digits are F. It is the largest number one byte can hold.
How do I convert a decimal colour like rgb(255, 128, 0) to hex?
Convert each channel to two hex digits and join them: 255 = FF, 128 = 80, 0 = 00, so the colour is #FF8000. The colour converter does all three at once.
Why does hex use letters?
Base 16 needs a single symbol for each value from 0 to 15, but there are only ten numerals. The letters A to F fill the gap for 10 to 15.