Hex to CMYK
This page opens the RGB to CMYK converter on its HEX side, so the hex box is the first thing on screen whichever direction you last used here. Paste #0B7A85 into it and the left pane answers with the channels it read, R 11, G 122, B 133, while the right pane prints the arithmetic that produced the ink: K = 1 - max(R,G,B)/255, then C = (1 - R/255 - K) / (1 - K), and under it C 91.7%, M 8.3%, Y 0.0%, K 47.8%, a total ink of 147.8%, the round trip back to 11, 122, 133, and the line that matters most, no ICC profile applied. The hex box is forgiving about form and exact about content: the hash is optional and the page says how it read the code without one, 3 and 4 digit shorthand is expanded with a line showing the expansion, so 0b7 becomes #00BB77 and converts to C 100.0 M 0.0 Y 36.4 K 26.7, and the alpha pair of an 8 digit code is dropped with a line saying so, because CMYK has no alpha channel. Anything else is named rather than guessed at: a five digit code, a stray letter and a paste over 64 characters are each refused with the reason. The round trip is not a claim, it is a sweep: those four printed percentages, rounded to one decimal, convert back to the identical 0 to 255 channels for all 16,777,216 colours. Total ink is reported and never limited, so a very dark saturated colour such as #000003 comes out at 298.8% and the panel says it is past the 240% a press starts refusing. Four direction buttons sit under the stage, and switching carries the colour across rather than dropping you back on old values.
Gamut, rule of thumb: no flag. This is not one of the bright, heavily inked colours process inks visibly fall short of. Still a rule of thumb about the colour, not a measurement of your press.
hash optional, shorthand expanded, computed here with no colour management of any kind.
RGB 11, 122, 133 is C 91.7%, M 8.3%, Y 0.0%, K 47.8%, 147.8% total ink, no ICC profile applied.
- C 91.7 M 8.3 Y 0.0 K 47.8
- C 0.0 M 100.0 Y 100.0 K 0.0
- C 0.0 M 0.0 Y 0.0 K 100.0
Both directions run on the arithmetic printed beside the result, in this browser, with nothing uploaded and no account. Hex reads with or without the hash, 3 and 4 digit shorthand is expanded, and an alpha channel is dropped with a line saying so, because CMYK has no alpha. A channel outside 0 to 255, a percentage outside 0 to 100 or a box past 64 characters is named and refused rather than quietly corrected. The four percentages add up to the total ink shown, which this algebra keeps under 300% and never limits: past 240%, where a press starts refusing ink, the panel says so. The gamut line beside it is a rule of thumb about bright colours needing two process inks over 50%, not a measurement of any press. The direction and what you type stay in this browser, and the Start over button above the tool forgets them.
Common questions
- How do I convert a hex colour to CMYK?
- Type or paste it into the hex box this page opens on, with or without the leading hash and in either case. #0B7A85 gives C 91.7 M 8.3 Y 0.0 K 47.8, and typing 0B7A85 gives the same four numbers with a line noting that the hash is optional and the code was read as #0B7A85. Shorthand is expanded rather than rejected, so 0b7 is read as #00BB77, each digit doubled, and converts to C 100.0 M 0.0 Y 36.4 K 26.7. The Copy button under the readout puts the four percentages on the clipboard as C 91.7 M 8.3 Y 0.0 K 47.8.
- Which hex codes does it take, and what does it refuse?
- Three, four, six or eight digits. Three and four are expanded, and the eight digit form is converted with its alpha pair dropped and a line saying so, because CMYK has no alpha channel: #0B7A8580 is the same colour as #0B7A85. Everything else is refused by name rather than quietly corrected. A five digit code answers: That hex colour has 5 digits. A hex colour has 3, 4, 6 or 8 of them, as in #0B7 or #0B7A85. A stray letter is quoted back: G is not a hex digit. Hex runs 0 to 9 and then A to F, as in #0B7A85. The box itself reads up to 64 characters and says so when a longer paste arrives.
- Will my printer produce these numbers?
- No, and the page says so on the result itself rather than in a footnote: no ICC profile applied. This is the device independent algebra, which knows nothing about a press, an ink, a paper or a black generation strategy, and a profiled separation of the same colour returns different numbers for every profile it is given. That is also why nothing here limits the ink: #000003 comes out at C 100.0 M 100.0 Y 0.0 K 98.8, a total of 298.8%, and the panel flags it as past the 240% where a press starts refusing. Across the whole 8-bit colour space, 71,115 of the 16,777,216 colours ask for more than 240%, and they are all in that very dark, very saturated corner. When the job is going on a press, the print shop separates the file with their own profile.
- Can it go the other way, from CMYK back to hex?
- Yes: CMYK to HEX and CMYK to RGB are two of the four direction buttons, and the trip is lossless in this tool. C 91.7 M 8.3 Y 0.0 K 47.8 returns rgb(11, 122, 133) and #0B7A85, and that holds for every colour, not just this one: the percentages as printed convert back to the identical channels for all 16,777,216 of them, which the test suite sweeps rather than assumes. The CMYK panel prints that return trip on its own line while you work, so you can see it landed where it started, and switching direction carries the colour into the boxes the new direction reads from.
- What does the gamut line under the percentages mean?
- It is a rule of thumb about the colour you converted, not a measurement of any press, and it says which of the two it is every time it appears. A colour is flagged when its brightest channel is 200 or more out of 255 and the algebra asks for two process inks at 50% or more, which is the shape of the colours ink on paper visibly falls short of. #00FF00 is flagged, at C 100.0 M 0.0 Y 100.0 K 0.0, while orange #FFA500 is not, at C 0.0 M 35.3 Y 100.0 K 0.0. A flagged colour still converts, it simply prints duller than the swatch on your screen.
- Why does a grey hex code come out as black ink only?
- Because this mapping pulls everything achromatic into K. #808080 gives C 0.0 M 0.0 Y 0.0 K 49.8: the brightest channel sets K, and once K is taken out the three chromatic channels have nothing left to carry. #FFFFFF is C 0.0 M 0.0 Y 0.0 K 0.0, no ink at all, and #000000 is the one colour the chromatic formula cannot answer, since K is 1 and the division is by zero, so it is defined directly as K 100.0. A separation made with a profile usually builds part of a grey from cyan, magenta and yellow instead, which is why its K reads lower than the number here.
- Does this page change the direction the tool page opens in?
- No. This page sets the HEX to CMYK direction on arrival, ahead of whatever this browser last remembered, and that choice belongs to the page rather than to you: until you press a direction button here, what gets saved is the direction the tool page already had. What you type is yours either way and is kept, so the colour you were working on is still in the box when you come back. Nothing is uploaded, there is no account, and the Start over button above the tool forgets the direction and the values together.
The straight algebraic conversion, computed from the channels you enter and printed with its formula. It is device independent, which is the honest limit: no ICC profile, no ink, no paper and no press is taken into account, so use it to convert and read channel values, never to predict what a printer will put on the page.