#21578B
Closest named color: Dusk Blue (#26538D). oklch(44.8% 0.103 250.5), rgb(33, 87, 139).
Aa
White text reads best on this color (7.49:1).
About this color
#21578B is a dark, moderately saturated blue. In OKLCH its lightness is 45%, its chroma 0.103 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Dusk Blue (#26538D), ΔE 0.013 away. White text reads best on it, at 7.49:1.
| Hue family | Blues |
| Lightness | dark (45%) |
| Chroma | moderately saturated (0.103) |
| Temperature | cool |
| Nearest name | Dusk Blue (#26538D) |
| Black text | 2.80:1 |
| White text | 7.49:1 |
Values
| HEX | #21578B |
| RGB | rgb(33, 87, 139) |
| HSL | hsl(209, 62%, 34%) |
| OKLCH | oklch(44.8% 0.103 250.5) |
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 #21578B | 7.49:1 | AAA | Lc -90.6 | Preferred for body text |
| Black text on #21578B | 2.80:1 | Fails | Lc 18.3 | Dividers and decoration only |
| #21578B text on white | 7.49:1 | AAA | Lc 85.7 | Fine for body text |
| #21578B text on black | 2.80:1 | Fails | Lc -16.3 | Dividers and decoration only |
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
#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
#A4C4E7
oklch(80.9% 0.061 250.9)
-
Step 400
400
#72A5DB
oklch(70.7% 0.096 250.7)
-
Step 500
500
#4B8DD1
oklch(63% 0.123 251)
-
Step 600
600
#2A76BE
oklch(55.6% 0.134 250.7)
-
Step 700
700
#1C63A4
oklch(49.1% 0.124 250.6)
-
Step 800
800 (this color)
#21578B
oklch(44.8% 0.103 250.5)
-
Step 900
900
#1C446A
oklch(37.8% 0.079 249.7)
-
Step 950
950
#12283E
oklch(27.1% 0.05 250.2)
#21578B 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) | #3F5A8D | 0.033 |
| Deuteranopia (no green cones) | #2F508A | 0.022 |
| Tritanopia (no blue cones) | #00636A | 0.076 |
| Achromatopsia (no color) | #555555 | 0.103 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21578B
#21578B
oklch(44.8% 0.103 250.5)
- #764A00
#764A00
oklch(44.9% 0.097 70.8)
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 #21578B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dusk Blue #26538D ΔE 0.013
- Light Navy Blue #2E5A88 ΔE 0.016
- Deep Sea Blue #015482 ΔE 0.025
- Light Navy #155084 ΔE 0.025
- Denim Blue #3B5B92 ΔE 0.031
- Cobalt #1E488F ΔE 0.046
- Peacock Blue #016795 ΔE 0.046
- Denim #3B638C ΔE 0.047
Use #21578B 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.