#183F5B
Closest named color: Dark Blue Grey (#1F3B4D). oklch(35.4% 0.066 243), rgb(24, 63, 91).
Aa
White text reads best on this color (11.04:1).
About this color
#183F5B is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.066 and its hue 243°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.025 away. White text reads best on it, at 11.04:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.066) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.90:1 |
| White text | 11.04:1 |
Values
| HEX | #183F5B |
| RGB | rgb(24, 63, 91) |
| HSL | hsl(205, 58%, 23%) |
| OKLCH | oklch(35.4% 0.066 243) |
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 #183F5B | 11.04:1 | AAA | Lc -99.2 | Preferred for body text |
| Black text on #183F5B | 1.90:1 | Fails | Lc 8.6 | Not readable |
| #183F5B text on white | 11.04:1 | AAA | Lc 95.3 | Preferred for body text |
| #183F5B text on black | 1.90:1 | Fails | Lc -7.3 | 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
#CADCEA
oklch(88.5% 0.027 241.2)
-
Step 300
300
#A6C5DE
oklch(80.9% 0.049 242.6)
-
Step 400
400
#75A7CE
oklch(70.8% 0.078 242.6)
-
Step 500
500
#4E90C1
oklch(63% 0.1 242.7)
-
Step 600
600
#2F7AAE
oklch(55.7% 0.109 242.7)
-
Step 700
700
#206695
oklch(49% 0.101 242.8)
-
Step 800
800
#1D5379
oklch(42.6% 0.084 243.2)
-
Step 900
900 (this color)
#183F5B
oklch(35.4% 0.066 243)
-
Step 950
950
#132939
oklch(27.1% 0.041 242)
#183F5B 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) | #32405C | 0.031 |
| Deuteranopia (no green cones) | #29395A | 0.024 |
| Tritanopia (no blue cones) | #004649 | 0.047 |
| Achromatopsia (no color) | #3C3C3C | 0.066 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183F5B
#183F5B
oklch(35.4% 0.066 243)
- #533312
#533312
oklch(35.3% 0.065 63.4)
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 #183F5B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.025
- Dark Grey Blue #29465B ΔE 0.031
- Prussian Blue #1D3557 ΔE 0.031
- Midnight Green #073B4C ΔE 0.032
- Charcoal #264653 ΔE 0.034
- Marine Blue #01386A ΔE 0.041
- Twilight Blue #0A437A ΔE 0.053
- Onyx #343A40 ΔE 0.053
Use #183F5B 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.