#399CE0
Closest named color: Chefchaouen Blue (#4895EF). oklch(66.6% 0.135 243), rgb(57, 156, 224).
Aa
Black text reads best on this color (7.00:1).
About this color
#399CE0 is a medium-light, moderately saturated blue. In OKLCH its lightness is 67%, its chroma 0.135 and its hue 243°. Its hue sits on the cool side of the wheel. The nearest named color is Chefchaouen Blue (#4895EF), ΔE 0.034 away. Black text reads best on it, at 7.00:1.
| Hue family | Blues |
| Lightness | medium-light (67%) |
| Chroma | moderately saturated (0.135) |
| Temperature | cool |
| Nearest name | Chefchaouen Blue (#4895EF) |
| Black text | 7.00:1 |
| White text | 2.99:1 |
Values
| HEX | #399CE0 |
| RGB | rgb(57, 156, 224) |
| HSL | hsl(204, 73%, 55%) |
| OKLCH | oklch(66.6% 0.135 243) |
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 #399CE0 | 2.99:1 | Fails | Lc -61.6 | Content text, not long reading |
| Black text on #399CE0 | 7.00:1 | AAA | Lc 47.8 | Large or bold text, headings |
| #399CE0 text on white | 2.99:1 | Fails | Lc 56.3 | Large or bold text, headings |
| #399CE0 text on black | 7.00:1 | AAA | Lc -45.5 | 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
#DFECF6
oklch(93.6% 0.019 240.7)
-
Step 200
200
#C5DDF0
oklch(88.6% 0.037 241.8)
-
Step 300
300
#9CC6E9
oklch(80.9% 0.067 243.9)
-
Step 400
400
#62A8DD
oklch(70.7% 0.105 242.9)
-
Step 500
500 (this color)
#399CE0
oklch(66.6% 0.135 243)
-
Step 600
600
#007ABB
oklch(55.7% 0.134 242.9)
-
Step 700
700
#00669E
oklch(49% 0.119 243.2)
-
Step 800
800
#005482
oklch(42.8% 0.102 242.4)
-
Step 900
900
#05466C
oklch(37.8% 0.087 242.4)
-
Step 950
950
#08293F
oklch(27% 0.055 242.5)
#399CE0 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) | #7D9EE3 | 0.064 |
| Deuteranopia (no green cones) | #658EDF | 0.048 |
| Tritanopia (no blue cones) | #00ADB4 | 0.095 |
| Achromatopsia (no color) | #959595 | 0.136 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #399CE0
#399CE0
oklch(66.6% 0.135 243)
- #CD7F2A
#CD7F2A
oklch(66.5% 0.135 63.1)
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 #399CE0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Chefchaouen Blue #4895EF ΔE 0.034
- Dark Sky Blue #448EE4 ΔE 0.040
- Cornflower Blue #6495ED ΔE 0.045
- Dodger Blue #1E90FF ΔE 0.063
- Soft Blue #6488EA ΔE 0.065
- Faded Blue #658CBB ΔE 0.066
- Water Blue #0E87CC ΔE 0.068
- Cool Blue #4984B8 ΔE 0.079
Use #399CE0 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.