#4378D3
Closest named color: Windows Blue (#3778BF). oklch(58.2% 0.151 260.5), rgb(67, 120, 211).
Aa
Black text reads best on this color (4.86:1).
About this color
#4378D3 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.151 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.034 away. Black text reads best on it, at 4.86:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.151) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.86:1 |
| White text | 4.31:1 |
Values
| HEX | #4378D3 |
| RGB | rgb(67, 120, 211) |
| HSL | hsl(218, 62%, 55%) |
| OKLCH | oklch(58.2% 0.151 260.5) |
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 #4378D3 | 4.31:1 | AA large text | Lc -75.1 | Fine for body text |
| Black text on #4378D3 | 4.86:1 | AA | Lc 34.5 | Non-text elements, placeholder text |
| #4378D3 text on white | 4.31:1 | AA large text | Lc 69.6 | Content text, not long reading |
| #4378D3 text on black | 4.86:1 | AA | Lc -32.1 | 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
#E2EAF7
oklch(93.5% 0.02 260.2)
-
Step 200
200
#CBDAF3
oklch(88.5% 0.038 260.7)
-
Step 300
300
#A8C2ED
oklch(80.9% 0.067 260.4)
-
Step 400
400
#79A1E4
oklch(70.7% 0.108 260.4)
-
Step 500
500
#5688DD
oklch(63.1% 0.14 260.4)
-
Step 600
600 (this color)
#4378D3
oklch(58.2% 0.151 260.5)
-
Step 700
700
#2E5DAF
oklch(49.1% 0.141 260.7)
-
Step 800
800
#274D8E
oklch(42.8% 0.116 260.4)
-
Step 900
900
#244071
oklch(37.6% 0.091 260.8)
-
Step 950
950
#152642
oklch(27% 0.057 259.9)
#4378D3 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) | #4C81D7 | 0.027 |
| Deuteranopia (no green cones) | #3473D1 | 0.020 |
| Tritanopia (no blue cones) | #008D9B | 0.122 |
| Achromatopsia (no color) | #7A7A7A | 0.151 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #4378D3
#4378D3
oklch(58.2% 0.151 260.5)
- #9F7200
#9F7200
oklch(58.2% 0.12 81.1)
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 #4378D3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.034
- Royal Blue #4169E1 ΔE 0.047
- Water Blue #0E87CC ΔE 0.049
- Cool Blue #4984B8 ΔE 0.059
- Steel Blue #4682B4 ΔE 0.061
- Dark Sky Blue #448EE4 ΔE 0.061
- Cerulean Blue #056EEE ΔE 0.062
- French Blue #436BAD ΔE 0.064
Use #4378D3 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.