#183F58
Closest named color: Dark Blue Grey (#1F3B4D). oklch(35.2% 0.062 240), rgb(24, 63, 88).
Aa
White text reads best on this color (11.10:1).
About this color
#183F58 is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.062 and its hue 240°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.020 away. White text reads best on it, at 11.10:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.062) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.89:1 |
| White text | 11.10:1 |
Values
| HEX | #183F58 |
| RGB | rgb(24, 63, 88) |
| HSL | hsl(203, 57%, 22%) |
| OKLCH | oklch(35.2% 0.062 240) |
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 #183F58 | 11.10:1 | AAA | Lc -99.3 | Preferred for body text |
| Black text on #183F58 | 1.89:1 | Fails | Lc 8.4 | Not readable |
| #183F58 text on white | 11.10:1 | AAA | Lc 95.5 | Preferred for body text |
| #183F58 text on black | 1.89:1 | 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
#CBDCE9
oklch(88.6% 0.026 240.7)
-
Step 300
300
#A6C5DC
oklch(80.8% 0.047 240.3)
-
Step 400
400
#75A7CA
oklch(70.6% 0.074 239.7)
-
Step 500
500
#4F91BD
oklch(63.1% 0.095 239.8)
-
Step 600
600
#307AA9
oklch(55.5% 0.103 240.3)
-
Step 700
700
#216791
oklch(49.1% 0.096 239.7)
-
Step 800
800
#1E5476
oklch(42.7% 0.08 240.2)
-
Step 900
900 (this color)
#183F58
oklch(35.2% 0.062 240)
-
Step 950
950
#132938
oklch(27% 0.04 240.2)
#183F58 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) | #333F59 | 0.032 |
| Deuteranopia (no green cones) | #2B3958 | 0.027 |
| Tritanopia (no blue cones) | #004548 | 0.042 |
| Achromatopsia (no color) | #3C3C3C | 0.062 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183F58
#183F58
oklch(35.2% 0.062 240)
- #523317
#523317
oklch(35.2% 0.061 60.8)
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 #183F58, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.020
- Midnight Green #073B4C ΔE 0.028
- Dark Grey Blue #29465B ΔE 0.031
- Charcoal #264653 ΔE 0.032
- Prussian Blue #1D3557 ΔE 0.032
- Marine Blue #01386A ΔE 0.045
- Onyx #343A40 ΔE 0.049
- Gunmetal #293241 ΔE 0.051
Use #183F58 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.