#373CA9
Closest named color: Sapphire (#2138AB). oklch(42.4% 0.171 274.4), rgb(55, 60, 169).
Aa
White text reads best on this color (8.81:1).
About this color
#373CA9 is a dark, vivid blue. In OKLCH its lightness is 42%, its chroma 0.171 and its hue 274°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.030 away. White text reads best on it, at 8.81:1.
| Hue family | Blues |
| Lightness | dark (42%) |
| Chroma | vivid (0.171) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 2.38:1 |
| White text | 8.81:1 |
Values
| HEX | #373CA9 |
| RGB | rgb(55, 60, 169) |
| HSL | hsl(237, 51%, 44%) |
| OKLCH | oklch(42.4% 0.171 274.4) |
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 #373CA9 | 8.81:1 | AAA | Lc -94.1 | Preferred for body text |
| Black text on #373CA9 | 2.38:1 | Fails | Lc 14.4 | Not readable |
| #373CA9 text on white | 8.81:1 | AAA | Lc 89.6 | Fine for body text |
| #373CA9 text on black | 2.38:1 | Fails | Lc -12.6 | 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
#F2F5FF
oklch(97.1% 0.014 272.7)
-
Step 100
100
#E4E9FE
oklch(93.7% 0.029 275.2)
-
Step 200
200
#CDD7FF
oklch(88.4% 0.056 274.2)
-
Step 300
300
#ADBCFF
oklch(80.8% 0.096 274.3)
-
Step 400
400
#8597FF
oklch(70.8% 0.153 274.4)
-
Step 500
500
#6978FF
oklch(63.1% 0.199 274.4)
-
Step 600
600
#535AF2
oklch(55.6% 0.223 274.4)
-
Step 700
700
#4449D2
oklch(49.1% 0.206 274.2)
-
Step 800
800 (this color)
#373CA9
oklch(42.4% 0.171 274.4)
-
Step 900
900
#2F3687
oklch(37.8% 0.134 274.3)
-
Step 950
950
#1B204F
oklch(26.9% 0.086 274.6)
#373CA9 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) | #0050AC | 0.056 |
| Deuteranopia (no green cones) | #0045A7 | 0.044 |
| Tritanopia (no blue cones) | #00586D | 0.139 |
| Achromatopsia (no color) | #4A4A4A | 0.172 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373CA9
#373CA9
oklch(42.4% 0.171 274.4)
- #5E4D00
#5E4D00
oklch(42.5% 0.087 94.3)
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 #373CA9, closest first.
No curated palette has a color within ΔE 0.04 of #373CA9.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.030
- Blueberry #464196 ΔE 0.041
- Majorelle Blue #3F37C9 ΔE 0.052
- Blue Blue #2242C7 ΔE 0.053
- Dark Slate Blue #483D8B ΔE 0.056
- Cobalt #1E488F ΔE 0.058
- Indigo Blue #3A18B1 ΔE 0.060
- Blue With A Hint Of Purple #533CC6 ΔE 0.063
Use #373CA9 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.