#366DCB
Closest named color: Royal Blue (#4169E1). oklch(54.8% 0.157 260.4), rgb(54, 109, 203).
Aa
White text reads best on this color (4.99:1).
About this color
#366DCB is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.157 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.038 away. White text reads best on it, at 4.99:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.157) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.20:1 |
| White text | 4.99:1 |
Values
| HEX | #366DCB |
| RGB | rgb(54, 109, 203) |
| HSL | hsl(218, 59%, 50%) |
| OKLCH | oklch(54.8% 0.157 260.4) |
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 #366DCB | 4.99:1 | AA | Lc -79.6 | Fine for body text |
| Black text on #366DCB | 4.20:1 | AA large text | Lc 29.9 | Dividers and decoration only |
| #366DCB text on white | 4.99:1 | AA | Lc 74.1 | Content text, not long reading |
| #366DCB text on black | 4.20:1 | AA large text | Lc -27.6 | 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
#E2EAF8
oklch(93.5% 0.021 261.8)
-
Step 200
200
#CADAF4
oklch(88.4% 0.04 260.1)
-
Step 300
300
#A7C2EF
oklch(81% 0.07 260.6)
-
Step 400
400
#77A1E7
oklch(70.7% 0.113 260.3)
-
Step 500
500
#5488E0
oklch(63.2% 0.144 260.3)
-
Step 600
600 (this color)
#366DCB
oklch(54.8% 0.157 260.4)
-
Step 700
700
#2B5DB2
oklch(49.1% 0.146 260.3)
-
Step 800
800
#244C90
oklch(42.6% 0.121 260.3)
-
Step 900
900
#224073
oklch(37.7% 0.095 260.3)
-
Step 950
950
#152643
oklch(27% 0.059 260.5)
#366DCB 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) | #3B77CF | 0.028 |
| Deuteranopia (no green cones) | #1869C9 | 0.024 |
| Tritanopia (no blue cones) | #008392 | 0.124 |
| Achromatopsia (no color) | #6F6F6F | 0.157 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366DCB
#366DCB
oklch(54.8% 0.157 260.4)
- #936800
#936800
oklch(54.8% 0.113 80.1)
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 #366DCB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.038
- Windows Blue #3778BF ΔE 0.038
- Mid Blue #276AB3 ΔE 0.041
- French Blue #436BAD ΔE 0.047
- Cerulean Blue #056EEE ΔE 0.056
- Flat Blue #3C73A8 ΔE 0.061
- Warm Blue #4B57DB ΔE 0.062
- Dark Periwinkle #665FD1 ΔE 0.063
Use #366DCB 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.