#171B37
Closest named color: Rich Black (#0D1B2A). oklch(23.4% 0.054 275.3), rgb(23, 27, 55).
Aa
White text reads best on this color (16.82:1).
About this color
#171B37 is a very dark, muted blue. In OKLCH its lightness is 23%, its chroma 0.054 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Rich Black (#0D1B2A), ΔE 0.031 away. White text reads best on it, at 16.82:1.
| Hue family | Blues |
| Lightness | very dark (23%) |
| Chroma | muted (0.054) |
| Temperature | cool |
| Nearest name | Rich Black (#0D1B2A) |
| Black text | 1.24:1 |
| White text | 16.82:1 |
Values
| HEX | #171B37 |
| RGB | rgb(23, 27, 55) |
| HSL | hsl(233, 41%, 15%) |
| OKLCH | oklch(23.4% 0.054 275.3) |
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 #171B37 | 16.82:1 | AAA | Lc -106.1 | Preferred for body text |
| Black text on #171B37 | 1.24:1 | Fails | Lc 0.0 | Not readable |
| #171B37 text on white | 16.82:1 | AAA | Lc 103.7 | Preferred for body text |
| #171B37 text on black | 1.24:1 | Fails | Lc 0.0 | Not readable |
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 950.
-
Step 50
50
#F4F5FB
oklch(97.1% 0.008 278.6)
-
Step 100
100
#E6E9F7
oklch(93.6% 0.019 276.3)
-
Step 200
200
#D2D8F1
oklch(88.5% 0.035 274.9)
-
Step 300
300
#B4BEEA
oklch(80.9% 0.063 274.9)
-
Step 400
400
#8E9BE0
oklch(70.6% 0.102 275.3)
-
Step 500
500
#7481D7
oklch(63.1% 0.13 275.5)
-
Step 600
600
#5D69C5
oklch(55.6% 0.142 275.2)
-
Step 700
700
#4D57AA
oklch(49.1% 0.132 275.3)
-
Step 800
800
#3F478A
oklch(42.6% 0.11 275.6)
-
Step 900
900
#353C6E
oklch(37.6% 0.086 275.5)
-
Step 950
950 (this color)
#171B37
oklch(23.4% 0.054 275.3)
#171B37 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) | #101F38 | 0.015 |
| Deuteranopia (no green cones) | #0D1C36 | 0.015 |
| Tritanopia (no blue cones) | #0A2126 | 0.048 |
| Achromatopsia (no color) | #1D1D1D | 0.054 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #171B37
#171B37
oklch(23.4% 0.054 275.3)
- #251D00
#251D00
oklch(23.3% 0.048 94.4)
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 #171B37, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rich Black #0D1B2A ΔE 0.031
- Dark #1B2431 ΔE 0.037
- Oxford Blue #1B263B ΔE 0.038
- Jet #212529 ΔE 0.053
- Navy Blue #001146 ΔE 0.056
- Dark Indigo #1F0954 ΔE 0.070
- Space Cadet #2B2D42 ΔE 0.072
- Midnight Purple #280137 ΔE 0.072
Use #171B37 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.