#637EFB
Closest named color: Cornflower (#6A79F7). oklch(63.6% 0.188 271), rgb(99, 126, 251).
Aa
Black text reads best on this color (5.90:1).
About this color
#637EFB is a medium-light, vivid blue. In OKLCH its lightness is 64%, its chroma 0.188 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Cornflower (#6A79F7), ΔE 0.014 away. Black text reads best on it, at 5.90:1.
| Hue family | Blues |
| Lightness | medium-light (64%) |
| Chroma | vivid (0.188) |
| Temperature | cool |
| Nearest name | Cornflower (#6A79F7) |
| Black text | 5.90:1 |
| White text | 3.55:1 |
Values
| HEX | #637EFB |
| RGB | rgb(99, 126, 251) |
| HSL | hsl(229, 95%, 69%) |
| OKLCH | oklch(63.6% 0.188 271) |
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 #637EFB | 3.55:1 | AA large text | Lc -68.3 | Content text, not long reading |
| Black text on #637EFB | 5.90:1 | AA | Lc 41.3 | Non-text elements, placeholder text |
| #637EFB text on white | 3.55:1 | AA large text | Lc 62.8 | Content text, not long reading |
| #637EFB text on black | 5.90:1 | AA | Lc -38.9 | 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
#E3E9FC
oklch(93.5% 0.027 271.9)
-
Step 200
200
#CCD8FC
oklch(88.5% 0.051 270.8)
-
Step 300
300
#AABEFD
oklch(80.9% 0.092 270.6)
-
Step 400
400
#7F99FC
oklch(70.6% 0.148 271.1)
-
Step 500
500 (this color)
#637EFB
oklch(63.6% 0.188 271)
-
Step 600
600
#4B61E8
oklch(55.5% 0.204 271.1)
-
Step 700
700
#3D4FCA
oklch(49% 0.19 271.1)
-
Step 800
800
#3242A3
oklch(42.7% 0.157 271)
-
Step 900
900
#2B3981
oklch(37.6% 0.122 271.1)
-
Step 950
950
#19224C
oklch(27% 0.078 271.2)
#637EFB 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) | #398FFF | 0.051 |
| Deuteranopia (no green cones) | #1181F8 | 0.058 |
| Tritanopia (no blue cones) | #009BB1 | 0.161 |
| Achromatopsia (no color) | #888888 | 0.188 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637EFB
#637EFB
oklch(63.6% 0.188 271)
- #A98700
#A98700
oklch(63.7% 0.13 90.9)
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 #637EFB, closest first.
No curated palette has a color within ΔE 0.04 of #637EFB.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cornflower #6A79F7 ΔE 0.014
- Soft Blue #6488EA ΔE 0.039
- Clear Blue #247AFD ΔE 0.056
- Medium Slate Blue #7B68EE ΔE 0.058
- Periwinkle #8E82FE ΔE 0.060
- Dodger Blue #1E90FF ΔE 0.061
- Lavender Blue #8B88F8 ΔE 0.061
- Dark Sky Blue #448EE4 ΔE 0.063
Use #637EFB 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.