#637997
Closest named color: Grey Blue (#647D8E). oklch(57% 0.053 256.2), rgb(99, 121, 151).
Aa
Black text reads best on this color (4.71:1).
About this color
#637997 is a medium-dark, muted blue. In OKLCH its lightness is 57%, its chroma 0.053 and its hue 256°. Its hue sits on the cool side of the wheel. The nearest named color is Grey Blue (#647D8E), ΔE 0.021 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | muted (0.053) |
| Temperature | cool |
| Nearest name | Grey Blue (#647D8E) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #637997 |
| RGB | rgb(99, 121, 151) |
| HSL | hsl(215, 21%, 49%) |
| OKLCH | oklch(57% 0.053 256.2) |
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 #637997 | 4.45:1 | AA large text | Lc -76.4 | Fine for body text |
| Black text on #637997 | 4.71:1 | AA | Lc 33.2 | Non-text elements, placeholder text |
| #637997 text on white | 4.45:1 | AA large text | Lc 70.9 | Content text, not long reading |
| #637997 text on black | 4.71:1 | AA | Lc -30.8 | 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 600.
-
Step 50
50
#F4F5F8
oklch(97% 0.004 271.4)
-
Step 100
100
#E7EAEE
oklch(93.6% 0.006 255.5)
-
Step 200
200
#D4DAE2
oklch(88.6% 0.013 255.5)
-
Step 300
300
#B7C2D0
oklch(81% 0.023 254.4)
-
Step 400
400
#91A2B9
oklch(70.7% 0.039 256)
-
Step 500
500
#768BA7
oklch(63% 0.049 255.7)
-
Step 600
600 (this color)
#637997
oklch(57% 0.053 256.2)
-
Step 700
700
#4E627D
oklch(49.1% 0.05 256)
-
Step 800
800
#405066
oklch(42.7% 0.042 256.4)
-
Step 900
900
#374253
oklch(37.6% 0.033 259)
-
Step 950
950
#202730
oklch(27% 0.02 254.8)
#637997 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) | #6E7A98 | 0.016 |
| Deuteranopia (no green cones) | #687596 | 0.012 |
| Tritanopia (no blue cones) | #537F83 | 0.046 |
| Achromatopsia (no color) | #777777 | 0.053 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637997
#637997
oklch(57% 0.053 256.2)
- #8A7354
#8A7354
oklch(56.9% 0.053 74.7)
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 #637997, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Grey Blue #647D8E ΔE 0.021
- Stormy Blue #507B9C ΔE 0.023
- Slate Gray #708090 ΔE 0.032
- Battleship Grey #6B7C85 ΔE 0.033
- Cerulean #457B9D ΔE 0.034
- Metallic Blue #4F738E ΔE 0.034
- Dull Blue #49759C ΔE 0.036
- Battleship Gray #6C757D ΔE 0.039
Use #637997 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.