#183FB5
Closest named color: Sapphire (#2138AB). oklch(42.6% 0.191 264.8), rgb(24, 63, 181).
Aa
White text reads best on this color (8.68:1).
About this color
#183FB5 is a dark, vivid blue. In OKLCH its lightness is 43%, its chroma 0.191 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.023 away. White text reads best on it, at 8.68:1.
| Hue family | Blues |
| Lightness | dark (43%) |
| Chroma | vivid (0.191) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 2.41:1 |
| White text | 8.68:1 |
Values
| HEX | #183FB5 |
| RGB | rgb(24, 63, 181) |
| HSL | hsl(225, 77%, 40%) |
| OKLCH | oklch(42.6% 0.191 264.8) |
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 #183FB5 | 8.68:1 | AAA | Lc -93.5 | Preferred for body text |
| Black text on #183FB5 | 2.41:1 | Fails | Lc 15.0 | Dividers and decoration only |
| #183FB5 text on white | 8.68:1 | AAA | Lc 88.9 | Fine for body text |
| #183FB5 text on black | 2.41:1 | 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
#F1F6FF
oklch(97.2% 0.013 262.4)
-
Step 100
100
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C7D9FF
oklch(88.4% 0.056 265.2)
-
Step 300
300
#A2C0FF
oklch(80.9% 0.096 264.7)
-
Step 400
400
#719DFF
oklch(70.8% 0.152 264.6)
-
Step 500
500
#4C80FF
oklch(63.2% 0.197 264.6)
-
Step 600
600
#295EFF
oklch(55.5% 0.245 264.9)
-
Step 700
700
#1C4BE0
oklch(49% 0.231 264.8)
-
Step 800
800 (this color)
#183FB5
oklch(42.6% 0.191 264.8)
-
Step 900
900
#18388F
oklch(37.7% 0.149 264.7)
-
Step 950
950
#0F2254
oklch(27.1% 0.095 264.9)
#183FB5 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) | #0053B9 | 0.047 |
| Deuteranopia (no green cones) | #0044B3 | 0.014 |
| Tritanopia (no blue cones) | #005F74 | 0.147 |
| Achromatopsia (no color) | #4B4B4B | 0.192 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183FB5
#183FB5
oklch(42.6% 0.191 264.8)
- #654A00
#654A00
oklch(42.7% 0.087 84.5)
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 #183FB5, closest first.
No curated palette has a color within ΔE 0.04 of #183FB5.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.023
- Blue Blue #2242C7 ΔE 0.032
- Majorelle Blue #3F37C9 ΔE 0.052
- Cobalt #1E488F ΔE 0.067
- Indigo Blue #3A18B1 ΔE 0.070
- Blueberry #464196 ΔE 0.073
- Blue With A Hint Of Purple #533CC6 ΔE 0.077
- True Blue #010FCC ΔE 0.078
Use #183FB5 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.