#155B9B
Closest named color: Dusk Blue (#26538D). oklch(46.5% 0.123 251.1), rgb(21, 91, 155).
Aa
White text reads best on this color (6.99:1).
About this color
#155B9B is a medium-dark, moderately saturated blue. In OKLCH its lightness is 46%, its chroma 0.123 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Dusk Blue (#26538D), ΔE 0.029 away. White text reads best on it, at 6.99:1.
| Hue family | Blues |
| Lightness | medium-dark (46%) |
| Chroma | moderately saturated (0.123) |
| Temperature | cool |
| Nearest name | Dusk Blue (#26538D) |
| Black text | 3.00:1 |
| White text | 6.99:1 |
Values
| HEX | #155B9B |
| RGB | rgb(21, 91, 155) |
| HSL | hsl(209, 76%, 35%) |
| OKLCH | oklch(46.5% 0.123 251.1) |
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 #155B9B | 6.99:1 | AA | Lc -88.7 | Fine for body text |
| Black text on #155B9B | 3.00:1 | AA large text | Lc 20.3 | Dividers and decoration only |
| #155B9B text on white | 6.99:1 | AA | Lc 83.8 | Fine for body text |
| #155B9B text on black | 3.00:1 | AA large text | Lc -18.2 | Dividers and decoration only |
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 700.
-
Step 50
50
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF5
oklch(93.6% 0.017 250.8)
-
Step 200
200
#CADBEF
oklch(88.5% 0.033 252.5)
-
Step 300
300
#A5C4E7
oklch(80.9% 0.06 251.7)
-
Step 400
400
#73A5DA
oklch(70.7% 0.095 250.7)
-
Step 500
500
#4D8DD0
oklch(63.1% 0.121 251.3)
-
Step 600
600
#2D76BD
oklch(55.6% 0.132 251)
-
Step 700
700 (this color)
#155B9B
oklch(46.5% 0.123 251.1)
-
Step 800
800
#1C5184
oklch(42.7% 0.101 250.8)
-
Step 900
900
#1E436A
oklch(37.6% 0.079 251.8)
-
Step 950
950
#12283E
oklch(27.1% 0.05 250.2)
#155B9B 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) | #3B5F9E | 0.035 |
| Deuteranopia (no green cones) | #25549A | 0.020 |
| Tritanopia (no blue cones) | #006A73 | 0.090 |
| Achromatopsia (no color) | #595959 | 0.123 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #155B9B
#155B9B
oklch(46.5% 0.123 251.1)
- #7C4E00
#7C4E00
oklch(46.5% 0.1 70.8)
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 #155B9B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dusk Blue #26538D ΔE 0.029
- Denim Blue #3B5B92 ΔE 0.033
- Light Navy Blue #2E5A88 ΔE 0.034
- Peacock Blue #016795 ΔE 0.038
- Deep Sea Blue #015482 ΔE 0.045
- Light Navy #155084 ΔE 0.046
- Dusky Blue #475F94 ΔE 0.049
- Denim #3B638C ΔE 0.049
Use #155B9B 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.