#2578BB
Closest named color: Windows Blue (#3778BF). oklch(55.7% 0.13 247.6), rgb(37, 120, 187).
Aa
White text reads best on this color (4.68:1).
About this color
#2578BB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.130 and its hue 248°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.014 away. White text reads best on it, at 4.68:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.130) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.48:1 |
| White text | 4.68:1 |
Values
| HEX | #2578BB |
| RGB | rgb(37, 120, 187) |
| HSL | hsl(207, 67%, 44%) |
| OKLCH | oklch(55.7% 0.13 247.6) |
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 #2578BB | 4.68:1 | AA | Lc -77.6 | Fine for body text |
| Black text on #2578BB | 4.48:1 | AA large text | Lc 32.0 | Non-text elements, placeholder text |
| #2578BB text on white | 4.68:1 | AA | Lc 72.1 | Content text, not long reading |
| #2578BB text on black | 4.48:1 | AA large text | Lc -29.6 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF5
oklch(93.5% 0.017 248)
-
Step 200
200
#C9DCEE
oklch(88.6% 0.032 246.7)
-
Step 300
300
#A3C5E5
oklch(80.9% 0.058 247)
-
Step 400
400
#70A6D8
oklch(70.7% 0.093 247.4)
-
Step 500
500
#478FCE
oklch(63.2% 0.12 247.4)
-
Step 600
600 (this color)
#2578BB
oklch(55.7% 0.13 247.6)
-
Step 700
700
#1664A1
oklch(49% 0.121 247.9)
-
Step 800
800
#165282
oklch(42.7% 0.099 247.5)
-
Step 900
900
#1A4469
oklch(37.6% 0.079 248.2)
-
Step 950
950
#11283D
oklch(26.9% 0.049 248.1)
#2578BB 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) | #587BBE | 0.047 |
| Deuteranopia (no green cones) | #426EBA | 0.032 |
| Tritanopia (no blue cones) | #008890 | 0.094 |
| Achromatopsia (no color) | #747474 | 0.130 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2578BB
#2578BB
oklch(55.7% 0.13 247.6)
- #A26300
#A26300
oklch(55.7% 0.123 67.4)
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 #2578BB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.014
- Nice Blue #107AB0 ΔE 0.022
- Flat Blue #3C73A8 ΔE 0.032
- Mid Blue #276AB3 ΔE 0.039
- French Blue #436BAD ΔE 0.041
- Steel Blue #4682B4 ΔE 0.043
- Water Blue #0E87CC ΔE 0.044
- Muted Blue #3B719F ΔE 0.045
Use #2578BB 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.