#637CFB
Closest named color: Cornflower (#6A79F7). oklch(63.3% 0.19 271.6), rgb(99, 124, 251).
Aa
Black text reads best on this color (5.80:1).
About this color
#637CFB is a medium-light, vivid blue. In OKLCH its lightness is 63%, its chroma 0.190 and its hue 272°. Its hue sits on the cool side of the wheel. The nearest named color is Cornflower (#6A79F7), ΔE 0.011 away. Black text reads best on it, at 5.80:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | vivid (0.190) |
| Temperature | cool |
| Nearest name | Cornflower (#6A79F7) |
| Black text | 5.80:1 |
| White text | 3.61:1 |
Values
| HEX | #637CFB |
| RGB | rgb(99, 124, 251) |
| HSL | hsl(230, 95%, 69%) |
| OKLCH | oklch(63.3% 0.19 271.6) |
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 #637CFB | 3.61:1 | AA large text | Lc -68.9 | Content text, not long reading |
| Black text on #637CFB | 5.80:1 | AA | Lc 40.6 | Non-text elements, placeholder text |
| #637CFB text on white | 3.61:1 | AA large text | Lc 63.4 | Content text, not long reading |
| #637CFB text on black | 5.80:1 | AA | Lc -38.2 | 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
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E3E9FD
oklch(93.5% 0.028 272.5)
-
Step 200
200
#CDD8FC
oklch(88.5% 0.051 271.9)
-
Step 300
300
#ABBEFD
oklch(81% 0.092 271.3)
-
Step 400
400
#8099FD
oklch(70.8% 0.149 271.5)
-
Step 500
500 (this color)
#637CFB
oklch(63.3% 0.19 271.6)
-
Step 600
600
#4C60EA
oklch(55.5% 0.208 271.6)
-
Step 700
700
#3E4FCB
oklch(49.2% 0.191 271.4)
-
Step 800
800
#3341A4
oklch(42.6% 0.159 271.7)
-
Step 900
900
#2C3982
oklch(37.8% 0.123 271.6)
-
Step 950
950
#19224C
oklch(27% 0.078 271.2)
#637CFB 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) | #338EFF | 0.055 |
| Deuteranopia (no green cones) | #0080F8 | 0.061 |
| Tritanopia (no blue cones) | #0099B0 | 0.162 |
| Achromatopsia (no color) | #868686 | 0.190 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637CFB
#637CFB
oklch(63.3% 0.19 271.6)
- #A78600
#A78600
oklch(63.3% 0.129 91.3)
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 #637CFB, closest first.
No curated palette has a color within ΔE 0.04 of #637CFB.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cornflower #6A79F7 ΔE 0.011
- Soft Blue #6488EA ΔE 0.042
- Medium Slate Blue #7B68EE ΔE 0.054
- Clear Blue #247AFD ΔE 0.055
- Periwinkle #8E82FE ΔE 0.061
- Dodger Blue #1E90FF ΔE 0.064
- Lavender Blue #8B88F8 ΔE 0.064
- Dark Sky Blue #448EE4 ΔE 0.066
Use #637CFB 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.