#309BE4
Closest named color: Chefchaouen Blue (#4895EF). oklch(66.4% 0.144 243.7), rgb(48, 155, 228).
Aa
Black text reads best on this color (6.93:1).
About this color
#309BE4 is a medium-light, vivid blue. In OKLCH its lightness is 66%, its chroma 0.144 and its hue 244°. Its hue sits on the cool side of the wheel. The nearest named color is Chefchaouen Blue (#4895EF), ΔE 0.029 away. Black text reads best on it, at 6.93:1.
| Hue family | Blues |
| Lightness | medium-light (66%) |
| Chroma | vivid (0.144) |
| Temperature | cool |
| Nearest name | Chefchaouen Blue (#4895EF) |
| Black text | 6.93:1 |
| White text | 3.02:1 |
Values
| HEX | #309BE4 |
| RGB | rgb(48, 155, 228) |
| HSL | hsl(204, 77%, 54%) |
| OKLCH | oklch(66.4% 0.144 243.7) |
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 #309BE4 | 3.02:1 | AA large text | Lc -62.0 | Content text, not long reading |
| Black text on #309BE4 | 6.93:1 | AA | Lc 47.4 | Large or bold text, headings |
| #309BE4 text on white | 3.02:1 | AA large text | Lc 56.6 | Large or bold text, headings |
| #309BE4 text on black | 6.93:1 | AA | Lc -45.2 | 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
#F0F6FB
oklch(97% 0.009 242.8)
-
Step 100
100
#DFECF7
oklch(93.7% 0.02 243.4)
-
Step 200
200
#C4DDF2
oklch(88.6% 0.039 243.5)
-
Step 300
300
#9AC6EB
oklch(80.8% 0.07 244.2)
-
Step 400
400
#5EA8E1
oklch(70.7% 0.112 243.6)
-
Step 500
500 (this color)
#309BE4
oklch(66.4% 0.144 243.7)
-
Step 600
600
#0079BC
oklch(55.5% 0.136 243.9)
-
Step 700
700
#00669F
oklch(49.1% 0.12 243.6)
-
Step 800
800
#005383
oklch(42.6% 0.105 243.8)
-
Step 900
900
#00456E
oklch(37.6% 0.092 243.7)
-
Step 950
950
#062941
oklch(27% 0.059 243.6)
#309BE4 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) | #799DE7 | 0.064 |
| Deuteranopia (no green cones) | #608DE3 | 0.048 |
| Tritanopia (no blue cones) | #00ADB5 | 0.100 |
| Achromatopsia (no color) | #949494 | 0.144 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #309BE4
#309BE4
oklch(66.4% 0.144 243.7)
- #CF7D19
#CF7D19
oklch(66.4% 0.143 63.7)
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 #309BE4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Chefchaouen Blue #4895EF ΔE 0.029
- Dark Sky Blue #448EE4 ΔE 0.036
- Cornflower Blue #6495ED ΔE 0.045
- Dodger Blue #1E90FF ΔE 0.055
- Soft Blue #6488EA ΔE 0.063
- Water Blue #0E87CC ΔE 0.065
- Faded Blue #658CBB ΔE 0.071
- Cool Blue #4984B8 ΔE 0.080
Use #309BE4 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.