#428BBF
Closest named color: Cool Blue (#4984B8). oklch(61.3% 0.107 242.4), rgb(66, 139, 191).
Aa
Black text reads best on this color (5.67:1).
About this color
#428BBF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.107 and its hue 242°. Its hue sits on the cool side of the wheel. The nearest named color is Cool Blue (#4984B8), ΔE 0.020 away. Black text reads best on it, at 5.67:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.107) |
| Temperature | cool |
| Nearest name | Cool Blue (#4984B8) |
| Black text | 5.67:1 |
| White text | 3.69:1 |
Values
| HEX | #428BBF |
| RGB | rgb(66, 139, 191) |
| HSL | hsl(205, 49%, 50%) |
| OKLCH | oklch(61.3% 0.107 242.4) |
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 #428BBF | 3.69:1 | AA large text | Lc -69.8 | Content text, not long reading |
| Black text on #428BBF | 5.67:1 | AA | Lc 39.7 | Non-text elements, placeholder text |
| #428BBF text on white | 3.69:1 | AA large text | Lc 64.3 | Content text, not long reading |
| #428BBF text on black | 5.67:1 | AA | Lc -37.3 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E1EBF3
oklch(93.5% 0.015 241.8)
-
Step 200
200
#C9DCEB
oklch(88.5% 0.029 241.6)
-
Step 300
300
#A4C5E0
oklch(80.8% 0.052 243.1)
-
Step 400
400
#71A7D1
oklch(70.7% 0.084 242.8)
-
Step 500
500 (this color)
#428BBF
oklch(61.3% 0.107 242.4)
-
Step 600
600
#247AB1
oklch(55.6% 0.116 242)
-
Step 700
700
#156699
oklch(49% 0.109 242.9)
-
Step 800
800
#16547C
oklch(42.8% 0.09 242.2)
-
Step 900
900
#1A4564
oklch(37.6% 0.071 243.3)
-
Step 950
950
#11293A
oklch(27% 0.044 241.7)
#428BBF 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) | #748CC1 | 0.053 |
| Deuteranopia (no green cones) | #627FBE | 0.043 |
| Tritanopia (no blue cones) | #00989D | 0.079 |
| Achromatopsia (no color) | #858585 | 0.108 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #428BBF
#428BBF
oklch(61.3% 0.107 242.4)
- #B27439
#B27439
oklch(61.3% 0.108 61.9)
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 #428BBF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cool Blue #4984B8 ΔE 0.020
- Steel Blue #4682B4 ΔE 0.027
- Off Blue #5684AE ΔE 0.031
- Dusty Blue #5A86AD ΔE 0.032
- Blue NCS #118AB2 ΔE 0.035
- Faded Blue #658CBB ΔE 0.035
- Water Blue #0E87CC ΔE 0.036
- Dark Sky Blue #448EE4 ΔE 0.056
Use #428BBF 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.