#637CD8
Closest named color: Soft Blue (#6488EA). oklch(61% 0.142 270.3), rgb(99, 124, 216).
Aa
Black text reads best on this color (5.40:1).
About this color
#637CD8 is a medium-dark, vivid blue. In OKLCH its lightness is 61%, its chroma 0.142 and its hue 270°. Its hue sits on the cool side of the wheel. The nearest named color is Soft Blue (#6488EA), ΔE 0.038 away. Black text reads best on it, at 5.40:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | vivid (0.142) |
| Temperature | cool |
| Nearest name | Soft Blue (#6488EA) |
| Black text | 5.40:1 |
| White text | 3.88:1 |
Values
| HEX | #637CD8 |
| RGB | rgb(99, 124, 216) |
| HSL | hsl(227, 60%, 62%) |
| OKLCH | oklch(61% 0.142 270.3) |
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 #637CD8 | 3.88:1 | AA large text | Lc -71.6 | Content text, not long reading |
| Black text on #637CD8 | 5.40:1 | AA | Lc 38.0 | Non-text elements, placeholder text |
| #637CD8 text on white | 3.88:1 | AA large text | Lc 66.1 | Content text, not long reading |
| #637CD8 text on black | 5.40:1 | AA | Lc -35.5 | 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
#F3F5FC
oklch(97.1% 0.01 273.4)
-
Step 100
100
#E4EAF8
oklch(93.7% 0.02 267.3)
-
Step 200
200
#CFD9F4
oklch(88.6% 0.039 269.4)
-
Step 300
300
#AFBFEF
oklch(80.9% 0.07 270.4)
-
Step 400
400
#869DE6
oklch(70.8% 0.11 270.1)
-
Step 500
500 (this color)
#637CD8
oklch(61% 0.142 270.3)
-
Step 600
600
#526ACD
oklch(55.6% 0.155 270.4)
-
Step 700
700
#4358B1
oklch(49.2% 0.143 270.4)
-
Step 800
800
#37488F
oklch(42.6% 0.119 270.5)
-
Step 900
900
#2F3D72
oklch(37.6% 0.092 270.3)
-
Step 950
950
#1B2443
oklch(26.9% 0.059 269.9)
#637CD8 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) | #5587DC | 0.030 |
| Deuteranopia (no green cones) | #477CD6 | 0.031 |
| Tritanopia (no blue cones) | #25909F | 0.128 |
| Achromatopsia (no color) | #818181 | 0.142 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637CD8
#637CD8
oklch(61% 0.142 270.3)
- #A07F00
#A07F00
oklch(61.1% 0.125 90.4)
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 #637CD8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Soft Blue #6488EA ΔE 0.038
- Cornflower #6A79F7 ΔE 0.049
- Dark Sky Blue #448EE4 ΔE 0.052
- Windows Blue #3778BF ΔE 0.063
- Cool Blue #4984B8 ΔE 0.065
- Medium Slate Blue #7B68EE ΔE 0.068
- Cornflower Blue #6495ED ΔE 0.068
- Water Blue #0E87CC ΔE 0.068
Use #637CD8 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.