#428FCB
Closest named color: Cool Blue (#4984B8). oklch(62.8% 0.118 244.9), rgb(66, 143, 203).
Aa
Black text reads best on this color (6.02:1).
About this color
#428FCB is a medium-light, moderately saturated blue. In OKLCH its lightness is 63%, its chroma 0.118 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Cool Blue (#4984B8), ΔE 0.037 away. Black text reads best on it, at 6.02:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Cool Blue (#4984B8) |
| Black text | 6.02:1 |
| White text | 3.48:1 |
Values
| HEX | #428FCB |
| RGB | rgb(66, 143, 203) |
| HSL | hsl(206, 57%, 53%) |
| OKLCH | oklch(62.8% 0.118 244.9) |
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 #428FCB | 3.48:1 | AA large text | Lc -67.6 | Content text, not long reading |
| Black text on #428FCB | 6.02:1 | AA | Lc 41.9 | Non-text elements, placeholder text |
| #428FCB text on white | 3.48:1 | AA large text | Lc 62.2 | Content text, not long reading |
| #428FCB text on black | 6.02:1 | AA | Lc -39.5 | 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 500.
-
Step 50
50
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#E1EBF5
oklch(93.5% 0.017 248)
-
Step 200
200
#C8DCED
oklch(88.5% 0.032 243.7)
-
Step 300
300
#A2C5E4
oklch(80.8% 0.058 245.3)
-
Step 400
400
#6EA7D7
oklch(70.8% 0.093 245)
-
Step 500
500 (this color)
#428FCB
oklch(62.8% 0.118 244.9)
-
Step 600
600
#1C79B9
oklch(55.6% 0.129 244.9)
-
Step 700
700
#0A659F
oklch(49% 0.12 245.1)
-
Step 800
800
#105381
oklch(42.7% 0.099 244.9)
-
Step 900
900
#174568
oklch(37.7% 0.078 245.2)
-
Step 950
950
#0F293D
oklch(27.1% 0.049 244.3)
#428FCB 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) | #7491CE | 0.052 |
| Deuteranopia (no green cones) | #6183CA | 0.041 |
| Tritanopia (no blue cones) | #009EA4 | 0.088 |
| Achromatopsia (no color) | #898989 | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #428FCB
#428FCB
oklch(62.8% 0.118 244.9)
- #B97830
#B97830
oklch(62.8% 0.118 65)
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 #428FCB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cool Blue #4984B8 ΔE 0.037
- Water Blue #0E87CC ΔE 0.038
- Faded Blue #658CBB ΔE 0.038
- Dark Sky Blue #448EE4 ΔE 0.039
- Steel Blue #4682B4 ΔE 0.045
- Off Blue #5684AE ΔE 0.048
- Dusty Blue #5A86AD ΔE 0.048
- Blue NCS #118AB2 ΔE 0.050
Use #428FCB 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.