#637191
Closest named color: Metallic Blue (#4F738E). oklch(54.9% 0.053 266.3), rgb(99, 113, 145).
Aa
White text reads best on this color (4.88:1).
About this color
#637191 is a medium-dark, muted blue. In OKLCH its lightness is 55%, its chroma 0.053 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Metallic Blue (#4F738E), ΔE 0.027 away. White text reads best on it, at 4.88:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | muted (0.053) |
| Temperature | cool |
| Nearest name | Metallic Blue (#4F738E) |
| Black text | 4.30:1 |
| White text | 4.88:1 |
Values
| HEX | #637191 |
| RGB | rgb(99, 113, 145) |
| HSL | hsl(222, 19%, 48%) |
| OKLCH | oklch(54.9% 0.053 266.3) |
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 #637191 | 4.88:1 | AA | Lc -79.2 | Fine for body text |
| Black text on #637191 | 4.30:1 | AA large text | Lc 30.2 | Non-text elements, placeholder text |
| #637191 text on white | 4.88:1 | AA | Lc 73.8 | Content text, not long reading |
| #637191 text on black | 4.30:1 | AA large text | Lc -27.9 | Dividers and decoration only |
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
#E8EAEF
oklch(93.7% 0.007 268.5)
-
Step 200
200
#D5D9E2
oklch(88.5% 0.013 266.7)
-
Step 300
300
#B9C1D1
oklch(81% 0.024 264.4)
-
Step 400
400
#96A1B9
oklch(70.8% 0.037 265.9)
-
Step 500
500
#7C89A8
oklch(63.1% 0.049 267.1)
-
Step 600
600 (this color)
#637191
oklch(54.9% 0.053 266.3)
-
Step 700
700
#54607D
oklch(49% 0.049 267.1)
-
Step 800
800
#454F66
oklch(42.8% 0.04 266.4)
-
Step 900
900
#3A4153
oklch(37.6% 0.032 268.2)
-
Step 950
950
#222631
oklch(27% 0.021 269.3)
#637191 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) | #677392 | 0.008 |
| Deuteranopia (no green cones) | #626F90 | 0.006 |
| Tritanopia (no blue cones) | #56777C | 0.047 |
| Achromatopsia (no color) | #717171 | 0.053 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637191
#637191
oklch(54.9% 0.053 266.3)
- #7F704D
#7F704D
oklch(55% 0.054 87.4)
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 #637191, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Metallic Blue #4F738E ΔE 0.027
- Dull Blue #49759C ΔE 0.034
- Stormy Blue #507B9C ΔE 0.034
- Grey Blue #647D8E ΔE 0.037
- Battleship Gray #6C757D ΔE 0.039
- Cerulean #457B9D ΔE 0.042
- Battleship Grey #6B7C85 ΔE 0.044
- Grey Purple #826D8C ΔE 0.046
Use #637191 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.