#366FD5
Closest named color: Royal Blue (#4169E1). oklch(55.9% 0.168 261), rgb(54, 111, 213).
Aa
White text reads best on this color (4.78:1).
About this color
#366FD5 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.168 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.026 away. White text reads best on it, at 4.78:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.168) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.39:1 |
| White text | 4.78:1 |
Values
| HEX | #366FD5 |
| RGB | rgb(54, 111, 213) |
| HSL | hsl(218, 65%, 52%) |
| OKLCH | oklch(55.9% 0.168 261) |
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 #366FD5 | 4.78:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #366FD5 | 4.39:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #366FD5 text on white | 4.78:1 | AA | Lc 72.8 | Content text, not long reading |
| #366FD5 text on black | 4.39:1 | AA large text | Lc -28.9 | 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
#E2EAF9
oklch(93.5% 0.022 263.2)
-
Step 200
200
#CADAF6
oklch(88.5% 0.042 261.7)
-
Step 300
300
#A5C2F2
oklch(80.9% 0.075 260.4)
-
Step 400
400
#75A0EC
oklch(70.6% 0.122 261.3)
-
Step 500
500
#5187E6
oklch(63.2% 0.155 260.9)
-
Step 600
600 (this color)
#366FD5
oklch(55.9% 0.168 261)
-
Step 700
700
#285BB8
oklch(49% 0.157 261.2)
-
Step 800
800
#224B95
oklch(42.7% 0.13 261.1)
-
Step 900
900
#213F76
oklch(37.6% 0.101 261.4)
-
Step 950
950
#142645
oklch(27.1% 0.063 260.6)
#366FD5 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) | #367AD9 | 0.029 |
| Deuteranopia (no green cones) | #006CD3 | 0.028 |
| Tritanopia (no blue cones) | #008798 | 0.131 |
| Achromatopsia (no color) | #727272 | 0.168 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366FD5
#366FD5
oklch(55.9% 0.168 261)
- #966C00
#966C00
oklch(55.9% 0.115 81.6)
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 #366FD5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.026
- Cerulean Blue #056EEE ΔE 0.043
- Windows Blue #3778BF ΔE 0.045
- Neon Blue #4361EE ΔE 0.053
- Mid Blue #276AB3 ΔE 0.056
- Warm Blue #4B57DB ΔE 0.060
- French Blue #436BAD ΔE 0.062
- Dark Periwinkle #665FD1 ΔE 0.062
Use #366FD5 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.