Convert RGB to CMYK – check print colors before press
Screen colors and printed colors differ. Verify CMYK values early — before InDesign, Illustrator, or your US/UK print shop flags a gamut issue.
When do you need to convert RGB to CMYK?
Every design that starts on screen — Figma mockups, Photoshop comps, Illustrator logos — uses RGB. The moment that design goes to a US or UK commercial printer, magazine publisher, or packaging manufacturer, the file must be in CMYK. RGB and CMYK use fundamentally different physics: RGB adds light, CMYK subtracts ink from white paper. A bright Figma blue like rgb(59, 130, 246) may print noticeably duller without prior gamut checking.
Adobe InDesign and Illustrator let you define swatch colors in CMYK directly, but you still need the values to enter. Brand guidelines often provide RGB and Pantone references — this converter lets you derive the CMYK equivalent for spot-to-process matching or magazine ad submissions that specify CMYK-only files.
Book covers, retail packaging, and business card print runs in the UK and US typically require files with total ink coverage (TIC) under 300%. Checking your CMYK values here before opening InDesign saves costly reprints.
All calculations run locally in your browser — nothing is sent to any server.
How does RGB to CMYK conversion work?
First, normalize RGB to 0–1 range: R'=R/255, G'=G/255, B'=B/255. K = 1 − max(R', G', B'). C = (1−R'−K)/(1−K). M = (1−G'−K)/(1−K). Y = (1−B'−K)/(1−K).
This is a mathematical conversion. Actual printed results depend on ink, paper, and ICC profiles. For production printing, use ICC profile-based conversion in Photoshop or InDesign.
This converter provides a mathematical estimate. For critical color work, always use proper ICC profiles and get a proof print.
RGB vs CMYK – comparison
| Feature | RGB | CMYK |
|---|---|---|
| Model | Additive (light) | Subtractive (ink) |
| Used for | Screens, web | Print, packaging |
| Gamut | Wider (more colors) | Narrower |
| Black | R=0, G=0, B=0 | K=100% |
| White | R=255, G=255, B=255 | No ink (paper) |
How to use the converter?
1. Enter a value
Type a number in the input field. You can use a period or comma as the decimal separator.2. Read the result
The conversion result appears instantly in the field next to it – no clicking required.3. Copy or reverse
Click Copy result or use the Reverse button to convert in the opposite direction.
When is this converter useful?
InDesign & Illustrator prep
Get exact C, M, Y, K percentages to enter into Adobe InDesign swatches or Illustrator color panels before sending files to a US or UK print shop.Pantone & brand color matching
Cross-reference RGB brand colors against CMYK equivalents for consistent reproduction across digital and print brand materials.Magazine & book publishing
Magazine ad submissions and book cover files require CMYK with TIC under 300%. Check values here before building the full InDesign document.Packaging & retail design
Packaging design for US and UK retailers requires CMYK files. Convert your digital mockup colors to check printability before the press run.
Practical tips
- Pure black: RGB(0,0,0) = CMYK(0,0,0,100). Rich black for print: CMYK(60,40,40,100).
- Pure white: RGB(255,255,255) = CMYK(0,0,0,0).
- Bright colors lose vibrancy in CMYK. Design with CMYK gamut in mind from the start.
- Total ink coverage should not exceed 300% for most printing processes.
Explore other unit converters
Frequently asked questions
Why do screen colors look different when printed?
Screens emit light using RGB (additive model) — mixing R+G+B=white. Printers deposit ink on paper using CMYK (subtractive model) — mixing C+M+Y+K=black. The CMYK gamut is roughly 50–70% of the RGB gamut, so vivid screen colors like Figma's electric blue or neon green simply cannot be reproduced with ink. Converting early lets you adjust expectations before the press run.
What is rich black and when should I use it?
Pure black in CMYK is K=100%, but this often looks slightly grey on large print areas. Rich black (typically C=60%, M=40%, Y=40%, K=100%) produces a deeper, denser black. Use rich black for headlines, large background areas, and covers. For small body text, use pure K=100% to avoid registration issues.
What is total ink coverage (TIC) and why does it matter?
TIC is the sum of C+M+Y+K percentages. Most commercial printers in the US and UK set a maximum of 300–320%. Exceeding it causes ink smearing, longer drying times, and paper damage. Check your CMYK values and sum the four channels before submitting print-ready files.
Should I design in RGB or CMYK from the start?
Design in RGB if your deliverable is primarily digital (web, app, social). Design in CMYK if print is the primary output. For dual-use projects — a brand identity that spans website and printed brochure — design in RGB and convert to CMYK for print delivery, using ICC profiles in Photoshop or InDesign for accurate conversion.
How does this converter differ from Photoshop's CMYK conversion?
This converter uses a mathematical formula (no ICC profile). It is ideal for quick checks, developer workflows, and ballpark values. Adobe Photoshop and InDesign use ICC color profiles (e.g., US Web Coated SWOP v2 or Fogra39) which account for specific ink and paper combinations. For production print work, always use ICC profile-based conversion and request a proof print.
Can I use CMYK values from this tool directly in InDesign?
Yes, as a starting reference. Open the Swatches panel in InDesign, create a CMYK swatch, and enter the C, M, Y, K percentages shown here. For critical color work — packaging, magazine covers, Pantone-matched brand colors — follow up with an ICC profile conversion and a physical proof.
Are my color values sent to a server?
No. All RGB to CMYK calculations run entirely in your browser. Nothing is transmitted anywhere. The tool works offline once the page has loaded.
Help us improve our tools
Have an idea, found a bug, or want to suggest a feature? Drop us a message – we respond within 24 hours.