#637FFF
Closest named color: Cornflower (#6A79F7). oklch(64.1% 0.192 270.8), rgb(99, 127, 255).
Aa
Black text reads best on this color (6.01:1).
About this color
#637FFF is a medium-light, vivid blue. In OKLCH its lightness is 64%, its chroma 0.192 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Cornflower (#6A79F7), ΔE 0.018 away. Black text reads best on it, at 6.01:1.
| Hue family | Blues |
| Lightness | medium-light (64%) |
| Chroma | vivid (0.192) |
| Temperature | cool |
| Nearest name | Cornflower (#6A79F7) |
| Black text | 6.01:1 |
| White text | 3.49:1 |
Values
| HEX | #637FFF |
| RGB | rgb(99, 127, 255) |
| HSL | hsl(229, 100%, 69%) |
| OKLCH | oklch(64.1% 0.192 270.8) |
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 #637FFF | 3.49:1 | AA large text | Lc -67.6 | Content text, not long reading |
| Black text on #637FFF | 6.01:1 | AA | Lc 41.9 | Non-text elements, placeholder text |
| #637FFF text on white | 3.49:1 | AA large text | Lc 62.2 | Content text, not long reading |
| #637FFF text on black | 6.01:1 | AA | Lc -39.5 | 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
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E3E9FD
oklch(93.5% 0.028 272.5)
-
Step 200
200
#CCD8FD
oklch(88.5% 0.053 271.1)
-
Step 300
300
#AABEFE
oklch(81% 0.094 270.8)
-
Step 400
400
#7E99FE
oklch(70.7% 0.151 270.8)
-
Step 500
500 (this color)
#637FFF
oklch(64.1% 0.192 270.8)
-
Step 600
600
#4A61EB
oklch(55.7% 0.208 270.8)
-
Step 700
700
#3C4FCC
oklch(49.1% 0.193 270.8)
-
Step 800
800
#3141A5
oklch(42.6% 0.161 270.9)
-
Step 900
900
#2A3983
oklch(37.7% 0.125 270.6)
-
Step 950
950
#19224D
oklch(27.1% 0.08 271.2)
#637FFF 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) | #3690FF | 0.052 |
| Deuteranopia (no green cones) | #0282FC | 0.060 |
| Tritanopia (no blue cones) | #009DB3 | 0.164 |
| Achromatopsia (no color) | #898989 | 0.192 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637FFF
#637FFF
oklch(64.1% 0.192 270.8)
- #AA8800
#AA8800
oklch(64% 0.131 91)
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 #637FFF, closest first.
No curated palette has a color within ΔE 0.04 of #637FFF.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cornflower #6A79F7 ΔE 0.018
- Soft Blue #6488EA ΔE 0.041
- Clear Blue #247AFD ΔE 0.057
- Periwinkle #8E82FE ΔE 0.058
- Dodger Blue #1E90FF ΔE 0.060
- Lavender Blue #8B88F8 ΔE 0.061
- Medium Slate Blue #7B68EE ΔE 0.061
- Dark Sky Blue #448EE4 ΔE 0.065
Use #637FFF 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.