#243CB9
Closest named color: Sapphire (#2138AB). oklch(42.9% 0.197 267.8), rgb(36, 60, 185).
Aa
White text reads best on this color (8.67:1).
About this color
#243CB9 is a dark, vivid blue. In OKLCH its lightness is 43%, its chroma 0.197 and its hue 268°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.025 away. White text reads best on it, at 8.67:1.
| Hue family | Blues |
| Lightness | dark (43%) |
| Chroma | vivid (0.197) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 2.42:1 |
| White text | 8.67:1 |
Values
| HEX | #243CB9 |
| RGB | rgb(36, 60, 185) |
| HSL | hsl(230, 67%, 43%) |
| OKLCH | oklch(42.9% 0.197 267.8) |
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 #243CB9 | 8.67:1 | AAA | Lc -93.5 | Preferred for body text |
| Black text on #243CB9 | 2.42:1 | Fails | Lc 15.1 | Dividers and decoration only |
| #243CB9 text on white | 8.67:1 | AAA | Lc 88.9 | Fine for body text |
| #243CB9 text on black | 2.42:1 | Fails | Lc -13.3 | 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 800.
-
Step 50
50
#F1F5FF
oklch(97% 0.014 268.5)
-
Step 100
100
#E1EAFF
oklch(93.7% 0.03 267.2)
-
Step 200
200
#C9D9FF
oklch(88.6% 0.055 267.2)
-
Step 300
300
#A6BFFF
oklch(80.9% 0.095 267.8)
-
Step 400
400
#789BFF
oklch(70.8% 0.152 267.9)
-
Step 500
500
#567DFF
oklch(63% 0.198 267.8)
-
Step 600
600
#395BFF
oklch(55.6% 0.245 267.9)
-
Step 700
700
#2B46E4
oklch(49.1% 0.238 267.8)
-
Step 800
800 (this color)
#243CB9
oklch(42.9% 0.197 267.8)
-
Step 900
900
#203591
oklch(37.6% 0.153 268)
-
Step 950
950
#122055
oklch(26.9% 0.098 267.9)
#243CB9 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) | #0053BD | 0.052 |
| Deuteranopia (no green cones) | #0044B7 | 0.023 |
| Tritanopia (no blue cones) | #005E75 | 0.152 |
| Achromatopsia (no color) | #4B4B4B | 0.198 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243CB9
#243CB9
oklch(42.9% 0.197 267.8)
- #644C00
#644C00
oklch(43% 0.088 87.7)
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 #243CB9, closest first.
No curated palette has a color within ΔE 0.04 of #243CB9.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.025
- Blue Blue #2242C7 ΔE 0.026
- Majorelle Blue #3F37C9 ΔE 0.041
- Indigo Blue #3A18B1 ΔE 0.062
- Blue With A Hint Of Purple #533CC6 ΔE 0.068
- Blurple #5539CC ΔE 0.073
- Blueberry #464196 ΔE 0.073
- Cobalt #1E488F ΔE 0.075
Use #243CB9 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.