#183E55
Closest named color: Dark Blue Grey (#1F3B4D). oklch(34.8% 0.059 238.3), rgb(24, 62, 85).
Aa
White text reads best on this color (11.29:1).
About this color
#183E55 is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.059 and its hue 238°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.015 away. White text reads best on it, at 11.29:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.059) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.85:1 |
| White text | 11.29:1 |
Values
| HEX | #183E55 |
| RGB | rgb(24, 62, 85) |
| HSL | hsl(203, 56%, 21%) |
| OKLCH | oklch(34.8% 0.059 238.3) |
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 #183E55 | 11.29:1 | AAA | Lc -99.7 | Preferred for body text |
| Black text on #183E55 | 1.85:1 | Fails | Lc 8.0 | Not readable |
| #183E55 text on white | 11.29:1 | AAA | Lc 95.9 | Preferred for body text |
| #183E55 text on black | 1.85:1 | 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 900.
-
Step 50
50
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E2EBF2
oklch(93.5% 0.014 241)
-
Step 200
200
#CBDCE8
oklch(88.5% 0.025 238.4)
-
Step 300
300
#A7C5DA
oklch(80.8% 0.044 238.6)
-
Step 400
400
#77A7C8
oklch(70.6% 0.071 239.1)
-
Step 500
500
#5191BA
oklch(63.1% 0.09 238.6)
-
Step 600
600
#327BA6
oklch(55.6% 0.098 238.1)
-
Step 700
700
#24678E
oklch(49% 0.091 238.4)
-
Step 800
800
#205473
oklch(42.6% 0.075 238.4)
-
Step 900
900 (this color)
#183E55
oklch(34.8% 0.059 238.3)
-
Step 950
950
#142937
oklch(27% 0.038 239.4)
#183E55 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) | #333E56 | 0.033 |
| Deuteranopia (no green cones) | #2B3855 | 0.027 |
| Tritanopia (no blue cones) | #004446 | 0.041 |
| Achromatopsia (no color) | #3A3A3A | 0.059 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183E55
#183E55
oklch(34.8% 0.059 238.3)
- #513219
#513219
oklch(34.9% 0.059 58)
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 #183E55, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.015
- Midnight Green #073B4C ΔE 0.023
- Prussian Blue #1D3557 ΔE 0.030
- Charcoal #264653 ΔE 0.033
- Dark Grey Blue #29465B ΔE 0.034
- Onyx #343A40 ΔE 0.046
- Gunmetal #293241 ΔE 0.046
- Marine Blue #01386A ΔE 0.047
Use #183E55 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.