#283F99
Closest named color: Cobalt (#1E488F). oklch(40.7% 0.15 268.1), rgb(40, 63, 153).
Aa
White text reads best on this color (9.28:1).
About this color
#283F99 is a dark, vivid blue. In OKLCH its lightness is 41%, its chroma 0.150 and its hue 268°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.030 away. White text reads best on it, at 9.28:1.
| Hue family | Blues |
| Lightness | dark (41%) |
| Chroma | vivid (0.150) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.26:1 |
| White text | 9.28:1 |
Values
| HEX | #283F99 |
| RGB | rgb(40, 63, 153) |
| HSL | hsl(228, 59%, 38%) |
| OKLCH | oklch(40.7% 0.15 268.1) |
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 #283F99 | 9.28:1 | AAA | Lc -95.3 | Preferred for body text |
| Black text on #283F99 | 2.26:1 | Fails | Lc 13.0 | Not readable |
| #283F99 text on white | 9.28:1 | AAA | Lc 91.0 | Preferred for body text |
| #283F99 text on black | 2.26:1 | Fails | Lc -11.4 | 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
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E2EAFB
oklch(93.6% 0.025 265.6)
-
Step 200
200
#CBD9FA
oklch(88.5% 0.048 267.2)
-
Step 300
300
#A8BFFA
oklch(80.9% 0.088 267.9)
-
Step 400
400
#7B9CF8
oklch(70.8% 0.14 267.8)
-
Step 500
500
#5C80F4
oklch(63.2% 0.178 268.1)
-
Step 600
600
#4466E3
oklch(55.7% 0.194 268)
-
Step 700
700
#3653C5
oklch(49% 0.181 268.1)
-
Step 800
800 (this color)
#283F99
oklch(40.7% 0.15 268.1)
-
Step 900
900
#273B7F
oklch(37.7% 0.118 268)
-
Step 950
950
#17234A
oklch(26.9% 0.074 268.3)
#283F99 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) | #004C9C | 0.037 |
| Deuteranopia (no green cones) | #004297 | 0.026 |
| Tritanopia (no blue cones) | #005565 | 0.119 |
| Achromatopsia (no color) | #474747 | 0.150 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #283F99
#283F99
oklch(40.7% 0.15 268.1)
- #5C4600
#5C4600
oklch(40.6% 0.083 88.1)
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 #283F99, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.030
- Sapphire #2138AB ΔE 0.035
- Blueberry #464196 ΔE 0.042
- Dark Slate Blue #483D8B ΔE 0.050
- Twilight Blue #0A437A ΔE 0.059
- Dusk Blue #26538D ΔE 0.060
- Light Navy #155084 ΔE 0.062
- Blue Blue #2242C7 ΔE 0.074
Use #283F99 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.