#183F55
Closest named color: Dark Blue Grey (#1F3B4D). oklch(35.1% 0.058 236.5), rgb(24, 63, 85).
Aa
White text reads best on this color (11.16:1).
About this color
#183F55 is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.058 and its hue 237°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.017 away. White text reads best on it, at 11.16:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.058) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.88:1 |
| White text | 11.16:1 |
Values
| HEX | #183F55 |
| RGB | rgb(24, 63, 85) |
| HSL | hsl(202, 56%, 21%) |
| OKLCH | oklch(35.1% 0.058 236.5) |
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 #183F55 | 11.16:1 | AAA | Lc -99.4 | Preferred for body text |
| Black text on #183F55 | 1.88:1 | Fails | Lc 8.3 | Not readable |
| #183F55 text on white | 11.16:1 | AAA | Lc 95.6 | Preferred for body text |
| #183F55 text on black | 1.88:1 | 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
#E2EBF1
oklch(93.5% 0.013 236.6)
-
Step 200
200
#CBDCE7
oklch(88.5% 0.024 236)
-
Step 300
300
#A7C6DA
oklch(81% 0.044 236.4)
-
Step 400
400
#76A8C7
oklch(70.8% 0.07 236.3)
-
Step 500
500
#5092B8
oklch(63.2% 0.088 235.8)
-
Step 600
600
#317BA5
oklch(55.6% 0.097 237.2)
-
Step 700
700
#22688D
oklch(49.2% 0.09 236.2)
-
Step 800
800
#1F5572
oklch(42.8% 0.074 235.8)
-
Step 900
900 (this color)
#183F55
oklch(35.1% 0.058 236.5)
-
Step 950
950
#132936
oklch(26.9% 0.037 236.3)
#183F55 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) | #353F56 | 0.035 |
| Deuteranopia (no green cones) | #2C3955 | 0.028 |
| Tritanopia (no blue cones) | #004546 | 0.041 |
| Achromatopsia (no color) | #3B3B3B | 0.058 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183F55
#183F55
oklch(35.1% 0.058 236.5)
- #52321B
#52321B
oklch(35.1% 0.058 55.2)
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 #183F55, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.017
- Midnight Green #073B4C ΔE 0.024
- Charcoal #264653 ΔE 0.030
- Dark Grey Blue #29465B ΔE 0.032
- Prussian Blue #1D3557 ΔE 0.034
- Onyx #343A40 ΔE 0.046
- Gunmetal #293241 ΔE 0.048
- Marine Blue #01386A ΔE 0.050
Use #183F55 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.