Royal Blue vs Cobalt

Royal Blue and Cobalt are both blues, but they are not the same color: the measured difference between their classic values is ΔE 13.4, clearly different colors.

Royal Blue

RGB: 65, 105, 225
HSL: 225, 73%, 57%
OKLCH: 56.0% 0.188 266.4

Temperature: cool

Closest encyclopedia entry: Royal Blue

Cobalt

RGB: 0, 71, 171
HSL: 215, 100%, 34%
OKLCH: 42.8% 0.172 259.7

Temperature: cool

Closest encyclopedia entry: Denim

Measured difference: ΔE 13.4 · clearly different colors. ΔE is a measure of perceived color difference; below 2.3 most people can't tell colors apart.

Guide

How to tell Royal Blue and Cobalt apart

1 Royal Blue is measurably lighter (13 points of OKLCH lightness). Squint: the one that survives is Cobalt.
2 Royal Blue carries more chroma, so it reads more saturated. Cobalt looks grayer in direct comparison.
3 Check them against a true neutral gray: subtle undertones surface immediately next to something with no undertone at all.

Guide

When to use which

Royal Blue passes AA for text on white (4.85:1), so it can work in type and trim, not just surfaces.

Cobalt passes AA for text on white (8.44:1), so it can work in type and trim, not just surfaces.

Palettes

Their palettes, side by side

Royal Blue complementary palette

Cobalt complementary palette

Royal Blue analogous palette

Cobalt analogous palette

FAQ

FAQs

Are Royal Blue and Cobalt the same color?

No. Using their classic reference values, they differ by ΔE 13.4 (a measure of perceived color difference; below 2.3 most people can't tell colors apart). That makes them clearly different colors.

Which is darker, Royal Blue or Cobalt?

Cobalt is darker: 13 points lower in OKLCH lightness than Royal Blue.