#637ACE
Closest named color: Soft Blue (#6488EA). oklch(60% 0.131 270.5), rgb(99, 122, 206).
Aa
Black text reads best on this color (5.20:1).
About this color
#637ACE is a medium-dark, moderately saturated blue. In OKLCH its lightness is 60%, its chroma 0.131 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Soft Blue (#6488EA), ΔE 0.051 away. Black text reads best on it, at 5.20:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | moderately saturated (0.131) |
| Temperature | cool |
| Nearest name | Soft Blue (#6488EA) |
| Black text | 5.20:1 |
| White text | 4.03:1 |
Values
| HEX | #637ACE |
| RGB | rgb(99, 122, 206) |
| HSL | hsl(227, 52%, 60%) |
| OKLCH | oklch(60% 0.131 270.5) |
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 #637ACE | 4.03:1 | AA large text | Lc -73.0 | Content text, not long reading |
| Black text on #637ACE | 5.20:1 | AA | Lc 36.6 | Non-text elements, placeholder text |
| #637ACE text on white | 4.03:1 | AA large text | Lc 67.4 | Content text, not long reading |
| #637ACE text on black | 5.20:1 | AA | Lc -34.2 | 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 500.
-
Step 50
50
#F3F5FB
oklch(97% 0.008 271.3)
-
Step 100
100
#E5EAF7
oklch(93.7% 0.018 269.1)
-
Step 200
200
#D0D9F1
oklch(88.6% 0.034 269.3)
-
Step 300
300
#B1BFEB
oklch(80.9% 0.064 271.1)
-
Step 400
400
#889DE1
oklch(70.7% 0.103 270.5)
-
Step 500
500 (this color)
#637ACE
oklch(60% 0.131 270.5)
-
Step 600
600
#546BC6
oklch(55.5% 0.143 270.5)
-
Step 700
700
#4559AB
oklch(49.1% 0.133 270.6)
-
Step 800
800
#39498A
oklch(42.6% 0.109 270.8)
-
Step 900
900
#313E6F
oklch(37.8% 0.085 270.7)
-
Step 950
950
#1C2441
oklch(26.9% 0.055 270.7)
#637ACE 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) | #5883D1 | 0.025 |
| Deuteranopia (no green cones) | #4C7ACC | 0.027 |
| Tritanopia (no blue cones) | #328C9A | 0.117 |
| Achromatopsia (no color) | #7E7E7E | 0.131 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637ACE
#637ACE
oklch(60% 0.131 270.5)
- #9C7C00
#9C7C00
oklch(60% 0.123 90.6)
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 #637ACE, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Soft Blue #6488EA ΔE 0.051
- Windows Blue #3778BF ΔE 0.053
- Cool Blue #4984B8 ΔE 0.056
- Steel Blue #4682B4 ΔE 0.059
- Dark Sky Blue #448EE4 ΔE 0.060
- Cornflower #6A79F7 ΔE 0.064
- Faded Blue #658CBB ΔE 0.064
- Off Blue #5684AE ΔE 0.064
Use #637ACE 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.