#3999D4
Closest named color: Dark Sky Blue (#448EE4). oklch(65.3% 0.125 239.9), rgb(57, 153, 212).
Aa
Black text reads best on this color (6.68:1).
About this color
#3999D4 is a medium-light, moderately saturated blue. In OKLCH its lightness is 65%, its chroma 0.125 and its hue 240°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Sky Blue (#448EE4), ΔE 0.043 away. Black text reads best on it, at 6.68:1.
| Hue family | Blues |
| Lightness | medium-light (65%) |
| Chroma | moderately saturated (0.125) |
| Temperature | cool |
| Nearest name | Dark Sky Blue (#448EE4) |
| Black text | 6.68:1 |
| White text | 3.14:1 |
Values
| HEX | #3999D4 |
| RGB | rgb(57, 153, 212) |
| HSL | hsl(203, 64%, 53%) |
| OKLCH | oklch(65.3% 0.125 239.9) |
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 #3999D4 | 3.14:1 | AA large text | Lc -63.6 | Content text, not long reading |
| Black text on #3999D4 | 6.68:1 | AA | Lc 45.9 | Large or bold text, headings |
| #3999D4 text on white | 3.14:1 | AA large text | Lc 58.2 | Large or bold text, headings |
| #3999D4 text on black | 6.68:1 | AA | Lc -43.6 | 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
#E0ECF5
oklch(93.7% 0.018 240)
-
Step 200
200
#C6DDEE
oklch(88.6% 0.034 239.9)
-
Step 300
300
#9DC7E4
oklch(80.9% 0.061 238.6)
-
Step 400
400
#64A9D7
oklch(70.7% 0.097 239.3)
-
Step 500
500 (this color)
#3999D4
oklch(65.3% 0.125 239.9)
-
Step 600
600
#007BB6
oklch(55.6% 0.128 240.2)
-
Step 700
700
#006799
oklch(49% 0.112 240)
-
Step 800
800
#00557F
oklch(42.8% 0.098 239.8)
-
Step 900
900
#094668
oklch(37.6% 0.081 240.2)
-
Step 950
950
#0A293D
oklch(26.9% 0.052 241)
#3999D4 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) | #7D99D7 | 0.065 |
| Deuteranopia (no green cones) | #688BD3 | 0.052 |
| Tritanopia (no blue cones) | #00A8AD | 0.085 |
| Achromatopsia (no color) | #919191 | 0.125 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3999D4
#3999D4
oklch(65.3% 0.125 239.9)
- #C77C37
#C77C37
oklch(65.4% 0.125 60.1)
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 #3999D4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Sky Blue #448EE4 ΔE 0.043
- Chefchaouen Blue #4895EF ΔE 0.047
- Faded Blue #658CBB ΔE 0.053
- Cornflower Blue #6495ED ΔE 0.056
- Water Blue #0E87CC ΔE 0.057
- Cool Blue #4984B8 ΔE 0.063
- Blue NCS #118AB2 ΔE 0.067
- Dusty Blue #5A86AD ΔE 0.069
Use #3999D4 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.