#2578DA
Closest named color: Windows Blue (#3778BF). oklch(57.7% 0.169 255.5), rgb(37, 120, 218).
Aa
Black text reads best on this color (4.77:1).
About this color
#2578DA is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.169 and its hue 256°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.042 away. Black text reads best on it, at 4.77:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.169) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.77:1 |
| White text | 4.39:1 |
Values
| HEX | #2578DA |
| RGB | rgb(37, 120, 218) |
| HSL | hsl(212, 71%, 50%) |
| OKLCH | oklch(57.7% 0.169 255.5) |
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 #2578DA | 4.39:1 | AA large text | Lc -75.4 | Fine for body text |
| Black text on #2578DA | 4.77:1 | AA | Lc 34.1 | Non-text elements, placeholder text |
| #2578DA text on white | 4.39:1 | AA large text | Lc 70.0 | Content text, not long reading |
| #2578DA text on black | 4.77:1 | AA | Lc -31.7 | Non-text elements, placeholder text |
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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E0EBF9
oklch(93.6% 0.022 254.4)
-
Step 200
200
#C7DBF5
oklch(88.5% 0.042 255)
-
Step 300
300
#A0C3F2
oklch(80.8% 0.077 255.9)
-
Step 400
400
#6BA3EB
oklch(70.7% 0.122 255.2)
-
Step 500
500
#418AE5
oklch(63.1% 0.155 255.4)
-
Step 600
600 (this color)
#2578DA
oklch(57.7% 0.169 255.5)
-
Step 700
700
#0D5FB7
oklch(49.2% 0.157 255.4)
-
Step 800
800
#104E94
oklch(42.8% 0.13 255.3)
-
Step 900
900
#174176
oklch(37.7% 0.102 256)
-
Step 950
950
#0F2745
oklch(27.1% 0.064 255.3)
#2578DA 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) | #4381DE | 0.035 |
| Deuteranopia (no green cones) | #1771D8 | 0.021 |
| Tritanopia (no blue cones) | #00909E | 0.129 |
| Achromatopsia (no color) | #787878 | 0.169 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2578DA
#2578DA
oklch(57.7% 0.169 255.5)
- #A26D00
#A26D00
oklch(57.6% 0.121 75.3)
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 #2578DA, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.042
- Royal Blue #4169E1 ΔE 0.042
- Cerulean Blue #056EEE ΔE 0.044
- Water Blue #0E87CC ΔE 0.049
- Clear Blue #247AFD ΔE 0.053
- Neon Blue #4361EE ΔE 0.067
- Dark Sky Blue #448EE4 ΔE 0.067
- Mid Blue #276AB3 ΔE 0.067
Use #2578DA 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.