RGB to HEX Converter

In short Going from RGB to HEX means writing each channel as two hexadecimal digits: rgb(58, 123, 213) becomes #3A7BD5. Every value from 0 to 255 has exactly one two-digit representation, so nothing is lost or rounded in either direction. Two details cause most of the errors. Alpha in hex is a fourth pair on the END — rgba(58, 123, 213, 0.5) is #3A7BD580, because 0.5 of 255 is 128, which is 80 in hex. People frequently write the alpha first, following the way some other formats do it, and get a completely different colour. And alpha in hex runs 00 to FF rather than 0 to 1, so a half-transparent colour is not #3A7BD50.5 or #3A7BD550. The other thing worth knowing is that shorthand only exists when both digits of every pair match: #FF0000 can be written #F00, but #FE0000 cannot be shortened at all. If a tool hands you a three-digit code for a colour that is not exactly representable, it has rounded your colour rather than abbreviated it, and the difference is visible on large areas.