Delta E calculator (color difference)
Compare a reference color with a sample. Type HEX, RGB or Lab values — all four common ΔE formulas update as you type.
What the numbers mean
| ΔE 2000 | Typical perception |
|---|---|
| < 1 | Not perceptible by the human eye |
| 1 – 2 | Perceptible on close inspection, side by side |
| 2 – 3.5 | Perceptible at a glance; common upper limit for brand colors in print |
| 3.5 – 5 | Clearly noticeable |
| 5 – 10 | Obvious difference |
| > 10 | Colors look like different colors |
These bands are a rule of thumb. Your customer or standard (for example ISO 12647 for print) may define different tolerances, and the same ΔE is more visible in some hues than others.
The four formulas
ΔE*76 (CIE76)
The straight-line distance in CIELAB: √(ΔL² + Δa² + Δb²). Simple, but it over-states differences in saturated colors and under-states them in blues and grays.
ΔE*94 (CIE94)
Weights chroma and hue differences by the chroma of the reference color. This page uses the graphic-arts constants (kL = 1, K1 = 0.045, K2 = 0.015). CIE94 is not symmetric — swapping reference and sample can change the result.
ΔE*00 (CIEDE2000)
The current CIE recommendation. It adds a hue-rotation term for blues, a lightness weighting around L* = 50 and a correction for near-neutral colors. The implementation here is checked against the published test data of Sharma, Wu and Dalal (2005).
CMC l:c
Developed for the textile industry. 2:1 is used for acceptability (lightness differences matter less), 1:1 for perceptibility. Like CIE94, it depends on which color is the reference.
From HEX or RGB to Lab
Screens describe colors in RGB; ΔE needs CIELAB. This calculator treats HEX and RGB as sRGB, linearizes them, converts to CIE XYZ, and then to Lab with a D65 white point and the 2° observer. Print workflows often use D50 instead, so values from a spectrophotometer or a print profile can differ slightly from what you see here — in that case enter the measured Lab values directly.
Questions
Can I paste values from Photoshop or a spectrophotometer?
Yes. Switch the input to Lab and type L*, a* and b*. Photoshop’s Lab is D50-based; for strict comparisons keep both colors from the same source.
Why does the swatch say “outside sRGB”?
Some Lab colors cannot be shown on a normal screen. The swatch shows the nearest displayable color; the ΔE numbers still use your exact Lab values.