#21517A
Closest named color: Deep Sea Blue (#015482). oklch(42.3% 0.086 247.4), rgb(33, 81, 122).
Aa
White text reads best on this color (8.32:1).
About this color
#21517A is a dark, moderately saturated blue. In OKLCH its lightness is 42%, its chroma 0.086 and its hue 247°. Its hue sits on the cool side of the wheel. The nearest named color is Deep Sea Blue (#015482), ΔE 0.019 away. White text reads best on it, at 8.32:1.
| Hue family | Blues |
| Lightness | dark (42%) |
| Chroma | moderately saturated (0.086) |
| Temperature | cool |
| Nearest name | Deep Sea Blue (#015482) |
| Black text | 2.52:1 |
| White text | 8.32:1 |
Values
| HEX | #21517A |
| RGB | rgb(33, 81, 122) |
| HSL | hsl(208, 57%, 30%) |
| OKLCH | oklch(42.3% 0.086 247.4) |
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 #21517A | 8.32:1 | AAA | Lc -93.1 | Preferred for body text |
| Black text on #21517A | 2.52:1 | Fails | Lc 15.5 | Dividers and decoration only |
| #21517A text on white | 8.32:1 | AAA | Lc 88.5 | Fine for body text |
| #21517A text on black | 2.52:1 | Fails | Lc -13.7 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF3
oklch(93.6% 0.015 244.7)
-
Step 200
200
#CBDBEB
oklch(88.4% 0.028 248.1)
-
Step 300
300
#A7C4E0
oklch(80.8% 0.051 247.5)
-
Step 400
400
#78A6D0
oklch(70.8% 0.079 246.7)
-
Step 500
500
#538FC4
oklch(63.2% 0.102 246.9)
-
Step 600
600
#3578B1
oklch(55.6% 0.112 247.2)
-
Step 700
700
#276598
oklch(49.2% 0.103 246.9)
-
Step 800
800 (this color)
#21517A
oklch(42.3% 0.086 247.4)
-
Step 900
900
#214463
oklch(37.6% 0.067 247.4)
-
Step 950
950
#14283A
oklch(26.9% 0.043 247.2)
#21517A 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) | #3F537C | 0.034 |
| Deuteranopia (no green cones) | #324A79 | 0.025 |
| Tritanopia (no blue cones) | #005B60 | 0.064 |
| Achromatopsia (no color) | #4E4E4E | 0.086 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21517A
#21517A
oklch(42.3% 0.086 247.4)
- #6C430E
#6C430E
oklch(42.2% 0.085 67.2)
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 #21517A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Deep Sea Blue #015482 ΔE 0.019
- Light Navy #155084 ΔE 0.019
- Dusk Blue #26538D ΔE 0.032
- Light Navy Blue #2E5A88 ΔE 0.037
- Cobalt #1E488F ΔE 0.048
- YInMn Blue #415A77 ΔE 0.048
- Twilight Blue #0A437A ΔE 0.048
- Dark Grey Blue #29465B ΔE 0.055
Use #21517A 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.