#6371BF
Closest named color: Windows Blue (#3778BF). oklch(57.3% 0.121 274.3), rgb(99, 113, 191).
Aa
Black text reads best on this color (4.64:1).
About this color
#6371BF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.121 and its hue 274°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.048 away. Black text reads best on it, at 4.64:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.121) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.64:1 |
| White text | 4.52:1 |
Values
| HEX | #6371BF |
| RGB | rgb(99, 113, 191) |
| HSL | hsl(231, 42%, 57%) |
| OKLCH | oklch(57.3% 0.121 274.3) |
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 #6371BF | 4.52:1 | AA | Lc -76.7 | Fine for body text |
| Black text on #6371BF | 4.64:1 | AA | Lc 32.8 | Non-text elements, placeholder text |
| #6371BF text on white | 4.52:1 | AA | Lc 71.3 | Content text, not long reading |
| #6371BF text on black | 4.64:1 | AA | Lc -30.4 | Non-text elements, placeholder text |
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
#F4F5FA
oklch(97.1% 0.007 277.2)
-
Step 100
100
#E6E9F5
oklch(93.5% 0.016 274.8)
-
Step 200
200
#D3D8EE
oklch(88.5% 0.031 275.6)
-
Step 300
300
#B5BFE5
oklch(81% 0.055 273.5)
-
Step 400
400
#909DD7
oklch(70.8% 0.086 274.3)
-
Step 500
500
#7583CD
oklch(63% 0.113 274.6)
-
Step 600
600 (this color)
#6371BF
oklch(57.3% 0.121 274.3)
-
Step 700
700
#4E5AA0
oklch(49.2% 0.112 274.2)
-
Step 800
800
#404A82
oklch(42.8% 0.093 274.2)
-
Step 900
900
#363E68
oklch(37.7% 0.073 274.2)
-
Step 950
950
#20243D
oklch(26.9% 0.047 275.9)
#6371BF 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) | #537AC2 | 0.028 |
| Deuteranopia (no green cones) | #4A73BD | 0.030 |
| Tritanopia (no blue cones) | #40818F | 0.106 |
| Achromatopsia (no color) | #767676 | 0.121 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #6371BF
#6371BF
oklch(57.3% 0.121 274.3)
- #8F7600
#8F7600
oklch(57.3% 0.117 94.1)
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 #6371BF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.048
- French Blue #436BAD ΔE 0.052
- Dark Periwinkle #665FD1 ΔE 0.057
- Flat Blue #3C73A8 ΔE 0.060
- Steel Blue #4682B4 ΔE 0.060
- Cool Blue #4984B8 ΔE 0.060
- Slate Blue #6A5ACD ΔE 0.065
- Off Blue #5684AE ΔE 0.066
Use #6371BF 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.