#2566CC
Closest named color: Royal Blue (#4169E1). oklch(52.8% 0.172 259.5), rgb(37, 102, 204).
Aa
White text reads best on this color (5.45:1).
About this color
#2566CC is a medium-dark, vivid blue. In OKLCH its lightness is 53%, its chroma 0.172 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.042 away. White text reads best on it, at 5.45:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | vivid (0.172) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 3.85:1 |
| White text | 5.45:1 |
Values
| HEX | #2566CC |
| RGB | rgb(37, 102, 204) |
| HSL | hsl(217, 69%, 47%) |
| OKLCH | oklch(52.8% 0.172 259.5) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #2566CC | 5.45:1 | AA | Lc -82.0 | Fine for body text |
| Black text on #2566CC | 3.85:1 | AA large text | Lc 27.4 | Dividers and decoration only |
| #2566CC text on white | 5.45:1 | AA | Lc 76.7 | Fine for body text |
| #2566CC text on black | 3.85:1 | AA large text | Lc -25.1 | Dividers and decoration only |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 600.
-
Step 50
50
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E1EBF9
oklch(93.7% 0.022 256.7)
-
Step 200
200
#C9DAF6
oklch(88.4% 0.043 260.4)
-
Step 300
300
#A3C2F3
oklch(80.9% 0.077 259.4)
-
Step 400
400
#71A1ED
oklch(70.7% 0.124 259.3)
-
Step 500
500
#4C87E7
oklch(63% 0.158 259.7)
-
Step 600
600 (this color)
#2566CC
oklch(52.8% 0.172 259.5)
-
Step 700
700
#215CB9
oklch(49.1% 0.159 259.5)
-
Step 800
800
#1D4C96
oklch(42.8% 0.132 259.4)
-
Step 900
900
#1D4077
oklch(37.7% 0.102 259.2)
-
Step 950
950
#122646
oklch(27.1% 0.065 259.4)
#2566CC with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #2671D0 | 0.029 |
| Deuteranopia (no green cones) | #0062CA | 0.020 |
| Tritanopia (no blue cones) | #007F8F | 0.133 |
| Achromatopsia (no color) | #696969 | 0.172 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2566CC
#2566CC
oklch(52.8% 0.172 259.5)
- #8C6200
#8C6200
oklch(52.7% 0.109 79.3)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #2566CC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.042
- Mid Blue #276AB3 ΔE 0.042
- Warm Blue #4B57DB ΔE 0.053
- Cerulean Blue #056EEE ΔE 0.054
- Azul #1D5DEC ΔE 0.055
- French Blue #436BAD ΔE 0.058
- Windows Blue #3778BF ΔE 0.059
- Neon Blue #4361EE ΔE 0.060
Use #2566CC in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.