#427FA4
Closest named color: Cerulean (#457B9D). oklch(57.1% 0.085 237.4), rgb(66, 127, 164).
Aa
Black text reads best on this color (4.80:1).
About this color
#427FA4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.085 and its hue 237°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.014 away. Black text reads best on it, at 4.80:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.085) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.80:1 |
| White text | 4.37:1 |
Values
| HEX | #427FA4 |
| RGB | rgb(66, 127, 164) |
| HSL | hsl(203, 43%, 45%) |
| OKLCH | oklch(57.1% 0.085 237.4) |
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 #427FA4 | 4.37:1 | AA large text | Lc -75.6 | Fine for body text |
| Black text on #427FA4 | 4.80:1 | AA | Lc 34.0 | Non-text elements, placeholder text |
| #427FA4 text on white | 4.37:1 | AA large text | Lc 70.1 | Content text, not long reading |
| #427FA4 text on black | 4.80:1 | AA | Lc -31.5 | 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
#F2F6F8
oklch(97.1% 0.005 228.8)
-
Step 100
100
#E3EBF0
oklch(93.5% 0.011 234.8)
-
Step 200
200
#CDDCE6
oklch(88.6% 0.021 236.8)
-
Step 300
300
#AAC5D7
oklch(80.9% 0.039 237.2)
-
Step 400
400
#7CA7C3
oklch(70.7% 0.062 237.3)
-
Step 500
500
#5991B3
oklch(63.1% 0.078 236.5)
-
Step 600
600 (this color)
#427FA4
oklch(57.1% 0.085 237.4)
-
Step 700
700
#2F6788
oklch(49.1% 0.079 237.3)
-
Step 800
800
#28546F
oklch(42.7% 0.066 238)
-
Step 900
900
#25465A
oklch(37.8% 0.052 236.9)
-
Step 950
950
#162934
oklch(27% 0.032 235.1)
#427FA4 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) | #6E7EA6 | 0.050 |
| Deuteranopia (no green cones) | #6074A3 | 0.042 |
| Tritanopia (no blue cones) | #00888B | 0.063 |
| Achromatopsia (no color) | #797979 | 0.085 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #427FA4
#427FA4
oklch(57.1% 0.085 237.4)
- #9E6B43
#9E6B43
oklch(57.3% 0.086 58.1)
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 #427FA4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.014
- Stormy Blue #507B9C ΔE 0.018
- Steel Blue #4682B4 ΔE 0.026
- Dull Blue #49759C ΔE 0.028
- Off Blue #5684AE ΔE 0.030
- Cool Blue #4984B8 ΔE 0.033
- Dusty Blue #5A86AD ΔE 0.036
- Blue NCS #118AB2 ΔE 0.038
Use #427FA4 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.