#183F5C
Closest named color: Dark Blue Grey (#1F3B4D). oklch(35.5% 0.067 243.9), rgb(24, 63, 92).
Aa
White text reads best on this color (11.02:1).
About this color
#183F5C is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.067 and its hue 244°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.026 away. White text reads best on it, at 11.02:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.067) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.90:1 |
| White text | 11.02:1 |
Values
| HEX | #183F5C |
| RGB | rgb(24, 63, 92) |
| HSL | hsl(206, 59%, 23%) |
| OKLCH | oklch(35.5% 0.067 243.9) |
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 #183F5C | 11.02:1 | AAA | Lc -99.1 | Preferred for body text |
| Black text on #183F5C | 1.90:1 | Fails | Lc 8.6 | Not readable |
| #183F5C text on white | 11.02:1 | AAA | Lc 95.3 | Preferred for body text |
| #183F5C text on black | 1.90:1 | Fails | Lc -7.4 | 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 900.
-
Step 50
50
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF3
oklch(93.6% 0.015 244.7)
-
Step 200
200
#CADCEB
oklch(88.6% 0.028 243.1)
-
Step 300
300
#A6C5DF
oklch(80.9% 0.05 243.7)
-
Step 400
400
#75A7CF
oklch(70.8% 0.079 243.3)
-
Step 500
500
#4E90C3
oklch(63.1% 0.103 243.8)
-
Step 600
600
#2E79AF
oklch(55.5% 0.111 243.8)
-
Step 700
700
#206697
oklch(49.2% 0.104 243.8)
-
Step 800
800
#1D537A
oklch(42.6% 0.086 243.9)
-
Step 900
900 (this color)
#183F5C
oklch(35.5% 0.067 243.9)
-
Step 950
950
#13293A
oklch(27.2% 0.042 243.6)
#183F5C 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) | #32405D | 0.031 |
| Deuteranopia (no green cones) | #29395B | 0.024 |
| Tritanopia (no blue cones) | #004649 | 0.049 |
| Achromatopsia (no color) | #3C3C3C | 0.067 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183F5C
#183F5C
oklch(35.5% 0.067 243.9)
- #543311
#543311
oklch(35.4% 0.067 63.1)
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 #183F5C, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.026
- Prussian Blue #1D3557 ΔE 0.031
- Dark Grey Blue #29465B ΔE 0.031
- Midnight Green #073B4C ΔE 0.033
- Charcoal #264653 ΔE 0.035
- Marine Blue #01386A ΔE 0.040
- Twilight Blue #0A437A ΔE 0.051
- Onyx #343A40 ΔE 0.055
Use #183F5C 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.