#4378D5
Closest named color: Windows Blue (#3778BF). oklch(58.3% 0.154 260.8), rgb(67, 120, 213).
Aa
Black text reads best on this color (4.88:1).
About this color
#4378D5 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.154 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.037 away. Black text reads best on it, at 4.88:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.154) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.88:1 |
| White text | 4.29:1 |
Values
| HEX | #4378D5 |
| RGB | rgb(67, 120, 213) |
| HSL | hsl(218, 63%, 55%) |
| OKLCH | oklch(58.3% 0.154 260.8) |
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 #4378D5 | 4.29:1 | AA large text | Lc -74.9 | Content text, not long reading |
| Black text on #4378D5 | 4.88:1 | AA | Lc 34.7 | Non-text elements, placeholder text |
| #4378D5 text on white | 4.29:1 | AA large text | Lc 69.4 | Content text, not long reading |
| #4378D5 text on black | 4.88:1 | AA | Lc -32.2 | 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
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E2EAF8
oklch(93.5% 0.021 261.8)
-
Step 200
200
#CBDAF3
oklch(88.5% 0.038 260.7)
-
Step 300
300
#A7C2EE
oklch(80.9% 0.069 260.1)
-
Step 400
400
#79A1E6
oklch(70.8% 0.111 260.9)
-
Step 500
500
#5688DE
oklch(63.2% 0.141 260.6)
-
Step 600
600 (this color)
#4378D5
oklch(58.3% 0.154 260.8)
-
Step 700
700
#2D5DB0
oklch(49.1% 0.142 260.5)
-
Step 800
800
#264C8F
oklch(42.6% 0.119 260.8)
-
Step 900
900
#244072
oklch(37.7% 0.092 261.1)
-
Step 950
950
#152643
oklch(27% 0.059 260.5)
#4378D5 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) | #4B81D9 | 0.027 |
| Deuteranopia (no green cones) | #3174D3 | 0.020 |
| Tritanopia (no blue cones) | #008E9C | 0.125 |
| Achromatopsia (no color) | #7A7A7A | 0.154 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #4378D5
#4378D5
oklch(58.3% 0.154 260.8)
- #A07200
#A07200
oklch(58.4% 0.121 80.5)
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 #4378D5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.037
- Royal Blue #4169E1 ΔE 0.045
- Water Blue #0E87CC ΔE 0.050
- Cerulean Blue #056EEE ΔE 0.060
- Dark Sky Blue #448EE4 ΔE 0.060
- Cool Blue #4984B8 ΔE 0.062
- Clear Blue #247AFD ΔE 0.062
- Steel Blue #4682B4 ΔE 0.063
Use #4378D5 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.