#123A5F
Closest named color: Prussian Blue (#1D3557). oklch(34.1% 0.079 249.9), rgb(18, 58, 95).
Aa
White text reads best on this color (11.69:1).
About this color
#123A5F is a dark, moderately saturated blue. In OKLCH its lightness is 34%, its chroma 0.079 and its hue 250°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.020 away. White text reads best on it, at 11.69:1.
| Hue family | Blues |
| Lightness | dark (34%) |
| Chroma | moderately saturated (0.079) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.79:1 |
| White text | 11.69:1 |
Values
| HEX | #123A5F |
| RGB | rgb(18, 58, 95) |
| HSL | hsl(209, 68%, 22%) |
| OKLCH | oklch(34.1% 0.079 249.9) |
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 #123A5F | 11.69:1 | AAA | Lc -100.3 | Preferred for body text |
| Black text on #123A5F | 1.79:1 | Fails | Lc 7.3 | Not readable |
| #123A5F text on white | 11.69:1 | AAA | Lc 96.6 | Preferred for body text |
| #123A5F text on black | 1.79:1 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF5
oklch(93.6% 0.017 250.8)
-
Step 200
200
#C9DBEF
oklch(88.4% 0.034 251)
-
Step 300
300
#A4C4E6
oklch(80.8% 0.059 250.1)
-
Step 400
400
#72A5D9
oklch(70.6% 0.094 249.7)
-
Step 500
500
#4B8ECF
oklch(63.2% 0.12 249.6)
-
Step 600
600
#2A77BC
oklch(55.7% 0.13 249.5)
-
Step 700
700
#1C63A2
oklch(49% 0.122 249.9)
-
Step 800
800
#1A5184
oklch(42.6% 0.102 250.2)
-
Step 900
900 (this color)
#123A5F
oklch(34.1% 0.079 249.9)
-
Step 950
950
#12283E
oklch(27.1% 0.05 250.2)
#123A5F 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) | #293C61 | 0.026 |
| Deuteranopia (no green cones) | #1D355E | 0.017 |
| Tritanopia (no blue cones) | #004348 | 0.058 |
| Achromatopsia (no color) | #383838 | 0.079 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #123A5F
#123A5F
oklch(34.1% 0.079 249.9)
- #503000
#503000
oklch(34.1% 0.074 69.9)
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 #123A5F, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.020
- Marine Blue #01386A ΔE 0.023
- Dark Blue Grey #1F3B4D ΔE 0.034
- Midnight Green #073B4C ΔE 0.037
- Marine #042E60 ΔE 0.041
- Dark Grey Blue #29465B ΔE 0.050
- Twilight Blue #0A437A ΔE 0.050
- Charcoal #264653 ΔE 0.054
Use #123A5F 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.