#637BE4
Closest named color: Cornflower (#6A79F7). oklch(61.6% 0.16 271.3), rgb(99, 123, 228).
Aa
Black text reads best on this color (5.48:1).
About this color
#637BE4 is a medium-dark, vivid blue. In OKLCH its lightness is 62%, its chroma 0.160 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Cornflower (#6A79F7), ΔE 0.031 away. Black text reads best on it, at 5.48:1.
| Hue family | Blues |
| Lightness | medium-dark (62%) |
| Chroma | vivid (0.160) |
| Temperature | cool |
| Nearest name | Cornflower (#6A79F7) |
| Black text | 5.48:1 |
| White text | 3.82:1 |
Values
| HEX | #637BE4 |
| RGB | rgb(99, 123, 228) |
| HSL | hsl(229, 70%, 64%) |
| OKLCH | oklch(61.6% 0.16 271.3) |
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 #637BE4 | 3.82:1 | AA large text | Lc -71.1 | Content text, not long reading |
| Black text on #637BE4 | 5.48:1 | AA | Lc 38.5 | Non-text elements, placeholder text |
| #637BE4 text on white | 3.82:1 | AA large text | Lc 65.6 | Content text, not long reading |
| #637BE4 text on black | 5.48:1 | AA | Lc -36.1 | 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
#F3F5FD
oklch(97.1% 0.011 274.9)
-
Step 100
100
#E4E9FA
oklch(93.5% 0.024 272.8)
-
Step 200
200
#CED8F7
oklch(88.4% 0.044 271.3)
-
Step 300
300
#AEBEF4
oklch(80.8% 0.079 271.7)
-
Step 400
400
#849BEF
oklch(70.7% 0.126 271.3)
-
Step 500
500 (this color)
#637BE4
oklch(61.6% 0.16 271.3)
-
Step 600
600
#5067D8
oklch(55.7% 0.174 271)
-
Step 700
700
#4254BB
oklch(49% 0.163 271.6)
-
Step 800
800
#364697
oklch(42.8% 0.133 271.3)
-
Step 900
900
#2E3B78
oklch(37.6% 0.105 271.5)
-
Step 950
950
#1B2346
oklch(26.9% 0.066 271.6)
#637BE4 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) | #4A88E8 | 0.038 |
| Deuteranopia (no green cones) | #387DE2 | 0.042 |
| Tritanopia (no blue cones) | #0992A4 | 0.143 |
| Achromatopsia (no color) | #828282 | 0.160 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637BE4
#637BE4
oklch(61.6% 0.16 271.3)
- #A18100
#A18100
oklch(61.6% 0.126 91.2)
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 #637BE4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cornflower #6A79F7 ΔE 0.031
- Soft Blue #6488EA ΔE 0.034
- Dark Sky Blue #448EE4 ΔE 0.054
- Medium Slate Blue #7B68EE ΔE 0.056
- Royal Blue #4169E1 ΔE 0.064
- Clear Blue #247AFD ΔE 0.065
- Cornflower Blue #6495ED ΔE 0.067
- Chefchaouen Blue #4895EF ΔE 0.068
Use #637BE4 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.