#637F8A
Closest named color: Grey Blue (#647D8E). oklch(57.9% 0.036 223.9), rgb(99, 127, 138).
Aa
Black text reads best on this color (4.93:1).
About this color
#637F8A is a medium-dark, muted teal or cyan. In OKLCH its lightness is 58%, its chroma 0.036 and its hue 224°. Its hue sits on the cool side of the wheel. The nearest named color is Grey Blue (#647D8E), ΔE 0.010 away. Black text reads best on it, at 4.93:1.
| Hue family | Teals and cyans |
| Lightness | medium-dark (58%) |
| Chroma | muted (0.036) |
| Temperature | cool |
| Nearest name | Grey Blue (#647D8E) |
| Black text | 4.93:1 |
| White text | 4.25:1 |
Values
| HEX | #637F8A |
| RGB | rgb(99, 127, 138) |
| HSL | hsl(197, 16%, 46%) |
| OKLCH | oklch(57.9% 0.036 223.9) |
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 #637F8A | 4.25:1 | AA large text | Lc -74.9 | Content text, not long reading |
| Black text on #637F8A | 4.93:1 | AA | Lc 34.7 | Non-text elements, placeholder text |
| #637F8A text on white | 4.25:1 | AA large text | Lc 69.4 | Content text, not long reading |
| #637F8A text on black | 4.93:1 | AA | Lc -32.3 | 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
#F4F6F6
oklch(97.2% 0.002 197.1)
-
Step 100
100
#E7EAEC
oklch(93.5% 0.004 236.5)
-
Step 200
200
#D3DADD
oklch(88.4% 0.009 225.1)
-
Step 300
300
#B6C3C8
oklch(80.9% 0.016 222.7)
-
Step 400
400
#90A5AD
oklch(70.8% 0.026 222.7)
-
Step 500
500
#748E99
oklch(63% 0.034 225.4)
-
Step 600
600 (this color)
#637F8A
oklch(57.9% 0.036 223.9)
-
Step 700
700
#4C656F
oklch(49.1% 0.034 224.4)
-
Step 800
800
#3F535A
oklch(42.8% 0.027 221.3)
-
Step 900
900
#35444A
oklch(37.6% 0.022 224.2)
-
Step 950
950
#1F282B
oklch(26.9% 0.014 220.1)
#637F8A 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) | #797D8B | 0.030 |
| Deuteranopia (no green cones) | #73798A | 0.026 |
| Tritanopia (no blue cones) | #578382 | 0.025 |
| Achromatopsia (no color) | #7B7B7B | 0.037 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637F8A
#637F8A
oklch(57.9% 0.036 223.9)
- #8D7369
#8D7369
oklch(57.8% 0.036 42.1)
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 #637F8A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Grey Blue #647D8E ΔE 0.010
- Battleship Grey #6B7C85 ΔE 0.013
- Steel Grey #6F828A ΔE 0.019
- Slate Gray #708090 ΔE 0.021
- Battleship Gray #6C757D ΔE 0.030
- Steel #738595 ΔE 0.032
- Medium Grey #7D7F7C ΔE 0.040
- Stormy Blue #507B9C ΔE 0.040
Use #637F8A 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.