Color Distance Calculator (ΔE)

"Are these two colors the same?" sounds simple until money rides on it — a printed batch versus the target, an ad versus the brand book, an exported asset versus the original. The naive answer, compare the RGB or HEX values, is worse than useless, because the distance between numbers in RGB has almost nothing to do with how different the colors look. The eye is exquisitely sensitive to some regions of color space and nearly blind in others; it can barely separate two deep blues that are numerically far apart, yet instantly distinguishes two greens that are numerically close. Treat all directions equally, as RGB distance does, and you'll fail pairs perception passes and pass pairs it fails.

Delta-E exists to fix exactly this. By measuring distance in a perceptually-uniform space, it makes the number track the eye: equal ΔE means equal visible difference, wherever you are in color space. The original ΔE76 was a plain Euclidean distance in LAB and got the idea right but the details wrong — it badly overstates differences among blues and saturated colors. CIEDE2000 is the fix the industry settled on: it reweights lightness, chroma and hue and adds a rotation term for the blue region, and it's now the figure quality-control standards, print shops and brand guidelines reference. OKLab distance is the modern, simpler alternative that behaves well for screen and web work.

The thresholds are the practical payoff. Under one ΔE, a difference is below the just-noticeable threshold — the colors are, for human purposes, identical. One to two takes a careful side-by-side to spot, which is why so many brand and print tolerances land at ΔE ≤ 2. Two to ten is obvious at a glance, and beyond that the colors are simply different. Knowing the band turns a vague worry into a pass/fail decision.

So this instrument shows all three metrics at once — so you can see ΔE76 overstate a blue difference while ΔE2000 reports the truth — alongside the band your pair falls into. Generate candidate colors in the Palette Generator, read either color in every format with the Converter, and confirm legibility in the Accessibility Checker.