#181F51
Closest named color: Dark Indigo (#1F0954). oklch(26.7% 0.091 272.6), rgb(24, 31, 81).
Aa
White text reads best on this color (15.51:1).
About this color
#181F51 is a dark, moderately saturated blue. In OKLCH its lightness is 27%, its chroma 0.091 and its hue 273°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Indigo (#1F0954), ΔE 0.048 away. White text reads best on it, at 15.51:1.
| Hue family | Blues |
| Lightness | dark (27%) |
| Chroma | moderately saturated (0.091) |
| Temperature | cool |
| Nearest name | Dark Indigo (#1F0954) |
| Black text | 1.35:1 |
| White text | 15.51:1 |
Values
| HEX | #181F51 |
| RGB | rgb(24, 31, 81) |
| HSL | hsl(233, 54%, 21%) |
| OKLCH | oklch(26.7% 0.091 272.6) |
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 #181F51 | 15.51:1 | AAA | Lc -104.9 | Preferred for body text |
| Black text on #181F51 | 1.35:1 | Fails | Lc 0.0 | Not readable |
| #181F51 text on white | 15.51:1 | AAA | Lc 102.2 | Preferred for body text |
| #181F51 text on black | 1.35:1 | 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
#F2F5FF
oklch(97.1% 0.014 272.7)
-
Step 100
100
#E3E9FF
oklch(93.6% 0.03 273.6)
-
Step 200
200
#CCD8FF
oklch(88.6% 0.055 271.8)
-
Step 300
300
#ABBDFF
oklch(80.9% 0.096 272.3)
-
Step 400
400
#8198FF
oklch(70.7% 0.153 272.5)
-
Step 500
500
#6479FF
oklch(63% 0.199 272.7)
-
Step 600
600
#4C57FC
oklch(55.5% 0.241 272.6)
-
Step 700
700
#3E46DC
oklch(49.2% 0.223 272.4)
-
Step 800
800
#333BB1
oklch(42.7% 0.184 272.7)
-
Step 900
900
#2B358C
oklch(37.8% 0.143 272.5)
-
Step 950
950 (this color)
#181F51
oklch(26.7% 0.091 272.6)
#181F51 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) | #002753 | 0.030 |
| Deuteranopia (no green cones) | #002250 | 0.025 |
| Tritanopia (no blue cones) | #002B34 | 0.076 |
| Achromatopsia (no color) | #242424 | 0.091 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #181F51
#181F51
oklch(26.7% 0.091 272.6)
- #2F2400
#2F2400
oklch(26.6% 0.054 91.5)
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 #181F51, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Indigo #1F0954 ΔE 0.048
- Marine #042E60 ΔE 0.049
- Oxford Blue #1B263B ΔE 0.050
- Midnight Blue #191970 ΔE 0.057
- Navy Blue #001146 ΔE 0.060
- Dark #1B2431 ΔE 0.065
- Space Cadet #2B2D42 ΔE 0.066
- Darkblue #030764 ΔE 0.068
Use #181F51 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.