#427BCF
Closest named color: Windows Blue (#3778BF). oklch(58.6% 0.143 258.1), rgb(66, 123, 207).
Aa
Black text reads best on this color (4.96:1).
About this color
#427BCF is a medium-dark, vivid blue. In OKLCH its lightness is 59%, its chroma 0.143 and its hue 258°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.028 away. Black text reads best on it, at 4.96:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | vivid (0.143) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.96:1 |
| White text | 4.22:1 |
Values
| HEX | #427BCF |
| RGB | rgb(66, 123, 207) |
| HSL | hsl(216, 59%, 54%) |
| OKLCH | oklch(58.6% 0.143 258.1) |
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 #427BCF | 4.22:1 | AA large text | Lc -74.4 | Content text, not long reading |
| Black text on #427BCF | 4.96:1 | AA | Lc 35.2 | Non-text elements, placeholder text |
| #427BCF text on white | 4.22:1 | AA large text | Lc 68.9 | Content text, not long reading |
| #427BCF text on black | 4.96:1 | AA | Lc -32.8 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF7
oklch(93.7% 0.019 255.5)
-
Step 200
200
#CBDAF1
oklch(88.4% 0.036 258.9)
-
Step 300
300
#A7C2EB
oklch(80.8% 0.065 258.6)
-
Step 400
400
#78A2E0
oklch(70.7% 0.102 258)
-
Step 500
500
#558AD8
oklch(63.2% 0.131 258)
-
Step 600
600 (this color)
#427BCF
oklch(58.6% 0.143 258.1)
-
Step 700
700
#2C5FAA
oklch(49.1% 0.132 258.2)
-
Step 800
800
#254E8A
oklch(42.7% 0.11 258.1)
-
Step 900
900
#23416E
oklch(37.6% 0.085 258.3)
-
Step 950
950
#152741
oklch(27.2% 0.054 257.6)
#427BCF 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) | #5482D2 | 0.028 |
| Deuteranopia (no green cones) | #3E75CD | 0.017 |
| Tritanopia (no blue cones) | #008E9B | 0.113 |
| Achromatopsia (no color) | #7B7B7B | 0.143 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #427BCF
#427BCF
oklch(58.6% 0.143 258.1)
- #A37100
#A37100
oklch(58.5% 0.122 78)
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 #427BCF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.028
- Water Blue #0E87CC ΔE 0.040
- Cool Blue #4984B8 ΔE 0.049
- Steel Blue #4682B4 ΔE 0.050
- Dark Sky Blue #448EE4 ΔE 0.056
- Royal Blue #4169E1 ΔE 0.057
- Nice Blue #107AB0 ΔE 0.059
- Flat Blue #3C73A8 ΔE 0.062
Use #427BCF 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.