#3F9DDB
Closest named color: Chefchaouen Blue (#4895EF). oklch(66.8% 0.127 241.4), rgb(63, 157, 219).
Aa
Black text reads best on this color (7.05:1).
About this color
#3F9DDB is a medium-light, moderately saturated blue. In OKLCH its lightness is 67%, its chroma 0.127 and its hue 241°. Its hue sits on the cool side of the wheel. The nearest named color is Chefchaouen Blue (#4895EF), ΔE 0.042 away. Black text reads best on it, at 7.05:1.
| Hue family | Blues |
| Lightness | medium-light (67%) |
| Chroma | moderately saturated (0.127) |
| Temperature | cool |
| Nearest name | Chefchaouen Blue (#4895EF) |
| Black text | 7.05:1 |
| White text | 2.97:1 |
Values
| HEX | #3F9DDB |
| RGB | rgb(63, 157, 219) |
| HSL | hsl(204, 68%, 55%) |
| OKLCH | oklch(66.8% 0.127 241.4) |
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 #3F9DDB | 2.97:1 | Fails | Lc -61.4 | Content text, not long reading |
| Black text on #3F9DDB | 7.05:1 | AAA | Lc 48.0 | Large or bold text, headings |
| #3F9DDB text on white | 2.97:1 | Fails | Lc 56.0 | Large or bold text, headings |
| #3F9DDB text on black | 7.05:1 | AAA | Lc -45.8 | Large or bold text, headings |
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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E0ECF5
oklch(93.7% 0.018 240)
-
Step 200
200
#C6DDEE
oklch(88.6% 0.034 239.9)
-
Step 300
300
#9DC6E6
oklch(80.8% 0.063 242)
-
Step 400
400
#65A8D9
oklch(70.6% 0.099 241.8)
-
Step 500
500 (this color)
#3F9DDB
oklch(66.8% 0.127 241.4)
-
Step 600
600
#007AB8
oklch(55.5% 0.131 241.7)
-
Step 700
700
#00679C
oklch(49.2% 0.116 241.5)
-
Step 800
800
#005480
oklch(42.6% 0.1 241.3)
-
Step 900
900
#0A4669
oklch(37.7% 0.082 241.2)
-
Step 950
950
#0A293E
oklch(27% 0.053 242.3)
#3F9DDB 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) | #809EDE | 0.063 |
| Deuteranopia (no green cones) | #6B8FDA | 0.050 |
| Tritanopia (no blue cones) | #00ACB3 | 0.087 |
| Achromatopsia (no color) | #969696 | 0.127 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F9DDB
#3F9DDB
oklch(66.8% 0.127 241.4)
- #CC8138
#CC8138
oklch(66.9% 0.127 61.6)
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 #3F9DDB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Chefchaouen Blue #4895EF ΔE 0.042
- Dark Sky Blue #448EE4 ΔE 0.046
- Cornflower Blue #6495ED ΔE 0.049
- Faded Blue #658CBB ΔE 0.061
- Soft Blue #6488EA ΔE 0.070
- Water Blue #0E87CC ΔE 0.071
- Dodger Blue #1E90FF ΔE 0.072
- Turquoise Blue #06B1C4 ΔE 0.076
Use #3F9DDB 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.