How to Convert RGB to HEX

The conversion in three steps

Each RGB channel is a whole number from 0 to 255. Each one becomes exactly two hexadecimal digits, and the three pairs are joined after a #.

• Divide the channel by 16. The whole part is the first hex digit.
• The remainder is the second hex digit.
• Digits 10 to 15 are written A to F. Repeat for red, green and blue.

rgb(59, 130, 246)
59  = 3 * 16 + 11  ->  3B
130 = 8 * 16 + 2   ->  82
246 = 15 * 16 + 6  ->  F6

#3B82F6

Alpha (transparency)

An 8-digit HEX code adds a fourth pair for alpha. Multiply the alpha value (0 to 1) by 255, round, and convert like any other channel. rgba(59, 130, 246, 0.5) gives 0.5 * 255 = 127.5, which rounds to 128, or 80 in hex, so the code is #3B82F680. Modern CSS also accepts the space-separated form rgb(59 130 246 / 50%).

3-digit shorthand

A 3-digit code such as #FA0 doubles every digit, so it means #FFAA00. A colour can only be shortened when each pair has two identical digits. #3B82F6 has no shorthand.

Code for the common languages

// JavaScript
const toHex = (r, g, b) =>
  "#" + [r, g, b].map(n => n.toString(16).padStart(2, "0")).join("").toUpperCase();
toHex(59, 130, 246);   // "#3B82F6"

# Python
r, g, b = 59, 130, 246
print("#{:02X}{:02X}{:02X}".format(r, g, b))   # #3B82F6

// C#
int r = 59, g = 130, b = 246;
string hex = 
quot;#{r:X2}{g:X2}{b:X2}";            // #3B82F6

Common mistakes

The RGB to HEX Converter accepts rgb(), rgba() and plain r, g, b input, and shows an error for values outside 0 to 255.

• Values above 255 or below 0 do not map to two hex digits. Check the range first.
• Forgetting the leading zero: 5 must be written 05, not 5.
• Mixing percentages and numbers: rgb(100%, 50%, 0%) is not rgb(100, 50, 0).
• Pasting a string such as rgb(59, 130, 246) into code that expects three separate numbers.