#366FC5
Closest named color: Windows Blue (#3778BF). oklch(54.8% 0.147 258.6), rgb(54, 111, 197).
Aa
White text reads best on this color (4.95:1).
About this color
#366FC5 is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.147 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.028 away. White text reads best on it, at 4.95:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.147) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.23:1 |
| White text | 4.95:1 |
Values
| HEX | #366FC5 |
| RGB | rgb(54, 111, 197) |
| HSL | hsl(216, 57%, 49%) |
| OKLCH | oklch(54.8% 0.147 258.6) |
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 #366FC5 | 4.95:1 | AA | Lc -79.4 | Fine for body text |
| Black text on #366FC5 | 4.23:1 | AA large text | Lc 30.1 | Non-text elements, placeholder text |
| #366FC5 text on white | 4.95:1 | AA | Lc 74.0 | Content text, not long reading |
| #366FC5 text on black | 4.23:1 | AA large text | Lc -27.7 | 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 600.
-
Step 50
50
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E2EAF7
oklch(93.5% 0.02 260.2)
-
Step 200
200
#CBDAF2
oklch(88.5% 0.037 259.8)
-
Step 300
300
#A7C2EC
oklch(80.8% 0.067 259.1)
-
Step 400
400
#78A2E2
oklch(70.7% 0.105 258.6)
-
Step 500
500
#5489DA
oklch(63.1% 0.135 258.6)
-
Step 600
600 (this color)
#366FC5
oklch(54.8% 0.147 258.6)
-
Step 700
700
#2B5FAD
oklch(49.2% 0.137 258.5)
-
Step 800
800
#244E8C
oklch(42.8% 0.113 258.2)
-
Step 900
900
#224170
oklch(37.7% 0.089 258.5)
-
Step 950
950
#152641
oklch(26.9% 0.056 259.3)
#366FC5 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) | #4477C8 | 0.027 |
| Deuteranopia (no green cones) | #2A6AC3 | 0.018 |
| Tritanopia (no blue cones) | #008390 | 0.116 |
| Achromatopsia (no color) | #707070 | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366FC5
#366FC5
oklch(54.8% 0.147 258.6)
- #956700
#956700
oklch(54.8% 0.114 78)
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 #366FC5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.028
- Mid Blue #276AB3 ΔE 0.034
- French Blue #436BAD ΔE 0.038
- Royal Blue #4169E1 ΔE 0.049
- Flat Blue #3C73A8 ΔE 0.049
- Nice Blue #107AB0 ΔE 0.053
- Muted Blue #3B719F ΔE 0.062
- Water Blue #0E87CC ΔE 0.064
Use #366FC5 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.