#288FDB
Closest named color: Dark Sky Blue (#448EE4). oklch(63% 0.146 246.1), rgb(40, 143, 219).
Aa
Black text reads best on this color (6.04:1).
About this color
#288FDB is a medium-light, vivid blue. In OKLCH its lightness is 63%, its chroma 0.146 and its hue 246°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Sky Blue (#448EE4), ΔE 0.023 away. Black text reads best on it, at 6.04:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | vivid (0.146) |
| Temperature | cool |
| Nearest name | Dark Sky Blue (#448EE4) |
| Black text | 6.04:1 |
| White text | 3.47:1 |
Values
| HEX | #288FDB |
| RGB | rgb(40, 143, 219) |
| HSL | hsl(205, 71%, 51%) |
| OKLCH | oklch(63% 0.146 246.1) |
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 #288FDB | 3.47:1 | AA large text | Lc -67.3 | Content text, not long reading |
| Black text on #288FDB | 6.04:1 | AA | Lc 42.2 | Non-text elements, placeholder text |
| #288FDB text on white | 3.47:1 | AA large text | Lc 61.8 | Content text, not long reading |
| #288FDB text on black | 6.04:1 | AA | Lc -39.8 | 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
#F0F6FC
oklch(97% 0.01 247.9)
-
Step 100
100
#DFECF7
oklch(93.7% 0.02 243.4)
-
Step 200
200
#C5DCF2
oklch(88.4% 0.039 247.1)
-
Step 300
300
#9BC6EC
oklch(80.9% 0.071 245.5)
-
Step 400
400
#60A7E3
oklch(70.7% 0.114 245.8)
-
Step 500
500 (this color)
#288FDB
oklch(63% 0.146 246.1)
-
Step 600
600
#0078C1
oklch(55.5% 0.143 246.2)
-
Step 700
700
#0065A3
oklch(49.1% 0.126 245.9)
-
Step 800
800
#005287
oklch(42.6% 0.111 246.5)
-
Step 900
900
#034570
oklch(37.8% 0.094 245.5)
-
Step 950
950
#072842
oklch(26.9% 0.061 246.8)
#288FDB 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) | #6B92DE | 0.057 |
| Deuteranopia (no green cones) | #5182DA | 0.041 |
| Tritanopia (no blue cones) | #00A1AB | 0.102 |
| Achromatopsia (no color) | #898989 | 0.146 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #288FDB
#288FDB
oklch(63% 0.146 246.1)
- #C17500
#C17500
oklch(63% 0.14 66.2)
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 #288FDB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Sky Blue #448EE4 ΔE 0.023
- Water Blue #0E87CC ΔE 0.033
- Chefchaouen Blue #4895EF ΔE 0.041
- Dodger Blue #1E90FF ΔE 0.054
- Cool Blue #4984B8 ΔE 0.056
- Soft Blue #6488EA ΔE 0.057
- Cornflower Blue #6495ED ΔE 0.059
- Steel Blue #4682B4 ΔE 0.062
Use #288FDB 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.