#00509F
Closest named color: Cobalt (#1E488F). oklch(43.8% 0.145 255.1), rgb(0, 80, 159).
Aa
White text reads best on this color (7.93:1).
About this color
#00509F is a dark, vivid blue. In OKLCH its lightness is 44%, its chroma 0.145 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.033 away. White text reads best on it, at 7.93:1.
| Hue family | Blues |
| Lightness | dark (44%) |
| Chroma | vivid (0.145) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.64:1 |
| White text | 7.93:1 |
Values
| HEX | #00509F |
| RGB | rgb(0, 80, 159) |
| HSL | hsl(210, 100%, 31%) |
| OKLCH | oklch(43.8% 0.145 255.1) |
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 #00509F | 7.93:1 | AAA | Lc -91.5 | Preferred for body text |
| Black text on #00509F | 2.64:1 | Fails | Lc 17.2 | Dividers and decoration only |
| #00509F text on white | 7.93:1 | AAA | Lc 86.8 | Fine for body text |
| #00509F text on black | 2.64:1 | Fails | Lc -15.3 | 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
#F0F6FD
oklch(97.1% 0.011 252.1)
-
Step 100
100
#DFEBFA
oklch(93.6% 0.024 254)
-
Step 200
200
#C5DBF8
oklch(88.4% 0.047 255.4)
-
Step 300
300
#9CC4F7
oklch(81% 0.084 254.7)
-
Step 400
400
#63A3F3
oklch(70.7% 0.135 254.8)
-
Step 500
500
#3389EF
oklch(63.1% 0.173 255.1)
-
Step 600
600
#0071DB
oklch(55.7% 0.183 255)
-
Step 700
700
#005EB9
oklch(49% 0.162 255.1)
-
Step 800
800 (this color)
#00509F
oklch(43.8% 0.145 255.1)
-
Step 900
900
#0C417B
oklch(37.7% 0.112 254.7)
-
Step 950
950
#0A2648
oklch(26.9% 0.072 255.3)
#00509F 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) | #1F58A2 | 0.029 |
| Deuteranopia (no green cones) | #004B9D | 0.014 |
| Tritanopia (no blue cones) | #006370 | 0.106 |
| Achromatopsia (no color) | #515151 | 0.145 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #00509F
#00509F
oklch(43.8% 0.145 255.1)
- #6F4900
#6F4900
oklch(43.7% 0.092 75)
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 #00509F, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.033
- Dusk Blue #26538D ΔE 0.037
- Light Navy #155084 ΔE 0.045
- Deep Sea Blue #015482 ΔE 0.051
- Light Navy Blue #2E5A88 ΔE 0.059
- Denim Blue #3B5B92 ΔE 0.060
- Sapphire #2138AB ΔE 0.062
- Blueberry #464196 ΔE 0.066
Use #00509F 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.