#288BD1
Closest named color: Water Blue (#0E87CC). oklch(61.5% 0.138 244.8), rgb(40, 139, 209).
Aa
Black text reads best on this color (5.70:1).
About this color
#288BD1 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.138 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.017 away. Black text reads best on it, at 5.70:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.138) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.70:1 |
| White text | 3.68:1 |
Values
| HEX | #288BD1 |
| RGB | rgb(40, 139, 209) |
| HSL | hsl(205, 68%, 49%) |
| OKLCH | oklch(61.5% 0.138 244.8) |
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 #288BD1 | 3.68:1 | AA large text | Lc -69.5 | Content text, not long reading |
| Black text on #288BD1 | 5.70:1 | AA | Lc 40.1 | Non-text elements, placeholder text |
| #288BD1 text on white | 3.68:1 | AA large text | Lc 64.0 | Content text, not long reading |
| #288BD1 text on black | 5.70:1 | AA | Lc -37.7 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E0ECF6
oklch(93.7% 0.019 243)
-
Step 200
200
#C5DCF1
oklch(88.4% 0.038 245.8)
-
Step 300
300
#9CC6EA
oklch(80.9% 0.068 244.6)
-
Step 400
400
#63A7DF
oklch(70.6% 0.108 245)
-
Step 500
500 (this color)
#288BD1
oklch(61.5% 0.138 244.8)
-
Step 600
600
#0079BF
oklch(55.7% 0.14 245)
-
Step 700
700
#0065A1
oklch(49% 0.124 245.1)
-
Step 800
800
#005385
oklch(42.7% 0.107 244.8)
-
Step 900
900
#08456E
oklch(37.7% 0.09 245.2)
-
Step 950
950
#092940
oklch(27.1% 0.056 244.1)
#288BD1 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) | #6A8ED4 | 0.058 |
| Deuteranopia (no green cones) | #527ED0 | 0.043 |
| Tritanopia (no blue cones) | #009CA4 | 0.097 |
| Achromatopsia (no color) | #858585 | 0.138 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #288BD1
#288BD1
oklch(61.5% 0.138 244.8)
- #BC7002
#BC7002
oklch(61.5% 0.138 64.8)
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 #288BD1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.017
- Dark Sky Blue #448EE4 ΔE 0.036
- Cool Blue #4984B8 ΔE 0.041
- Steel Blue #4682B4 ΔE 0.047
- Blue NCS #118AB2 ΔE 0.050
- Windows Blue #3778BF ΔE 0.054
- Chefchaouen Blue #4895EF ΔE 0.057
- Off Blue #5684AE ΔE 0.059
Use #288BD1 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.