#366FD4
Closest named color: Royal Blue (#4169E1). oklch(55.8% 0.167 260.9), rgb(54, 111, 212).
Aa
White text reads best on this color (4.79:1).
About this color
#366FD4 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.167 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.027 away. White text reads best on it, at 4.79:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.167) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.38:1 |
| White text | 4.79:1 |
Values
| HEX | #366FD4 |
| RGB | rgb(54, 111, 212) |
| HSL | hsl(218, 65%, 52%) |
| OKLCH | oklch(55.8% 0.167 260.9) |
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 #366FD4 | 4.79:1 | AA | Lc -78.3 | Fine for body text |
| Black text on #366FD4 | 4.38:1 | AA large text | Lc 31.2 | Non-text elements, placeholder text |
| #366FD4 text on white | 4.79:1 | AA | Lc 72.8 | Content text, not long reading |
| #366FD4 text on black | 4.38:1 | AA large text | Lc -28.8 | 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
#CADAF5
oklch(88.5% 0.041 260.9)
-
Step 300
300
#A5C2F2
oklch(80.9% 0.075 260.4)
-
Step 400
400
#75A0EB
oklch(70.6% 0.12 261)
-
Step 500
500
#5187E5
oklch(63.1% 0.153 260.7)
-
Step 600
600 (this color)
#366FD4
oklch(55.8% 0.167 260.9)
-
Step 700
700
#285CB7
oklch(49.2% 0.155 260.7)
-
Step 800
800
#224B94
oklch(42.6% 0.129 260.9)
-
Step 900
900
#214076
oklch(37.8% 0.1 260.7)
-
Step 950
950
#142645
oklch(27.1% 0.063 260.6)
#366FD4 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) | #377AD8 | 0.029 |
| Deuteranopia (no green cones) | #016BD2 | 0.029 |
| Tritanopia (no blue cones) | #008797 | 0.131 |
| Achromatopsia (no color) | #727272 | 0.167 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366FD4
#366FD4
oklch(55.8% 0.167 260.9)
- #966B00
#966B00
oklch(55.7% 0.115 80.8)
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 #366FD4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.027
- Windows Blue #3778BF ΔE 0.044
- Cerulean Blue #056EEE ΔE 0.045
- Neon Blue #4361EE ΔE 0.054
- Mid Blue #276AB3 ΔE 0.054
- French Blue #436BAD ΔE 0.060
- Warm Blue #4B57DB ΔE 0.060
- Dark Periwinkle #665FD1 ΔE 0.062
Use #366FD4 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.