#647B99
Closest named color: Grey Blue (#647D8E). oklch(57.6% 0.054 255.2), rgb(100, 123, 153).
Aa
Black text reads best on this color (4.83:1).
About this color
#647B99 is a medium-dark, muted blue. In OKLCH its lightness is 58%, its chroma 0.054 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Grey Blue (#647D8E), ΔE 0.020 away. Black text reads best on it, at 4.83:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | muted (0.054) |
| Temperature | cool |
| Nearest name | Grey Blue (#647D8E) |
| Black text | 4.83:1 |
| White text | 4.34:1 |
Values
| HEX | #647B99 |
| RGB | rgb(100, 123, 153) |
| HSL | hsl(214, 21%, 50%) |
| OKLCH | oklch(57.6% 0.054 255.2) |
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 #647B99 | 4.34:1 | AA large text | Lc -75.5 | Fine for body text |
| Black text on #647B99 | 4.83:1 | AA | Lc 34.0 | Non-text elements, placeholder text |
| #647B99 text on white | 4.34:1 | AA large text | Lc 70.1 | Content text, not long reading |
| #647B99 text on black | 4.83:1 | AA | Lc -31.6 | 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
#E7EAEF
oklch(93.6% 0.007 260.7)
-
Step 200
200
#D3DAE2
oklch(88.5% 0.013 251.6)
-
Step 300
300
#B6C2D0
oklch(80.9% 0.024 252.2)
-
Step 400
400
#91A2B9
oklch(70.7% 0.039 256)
-
Step 500
500
#768BA8
oklch(63.1% 0.05 256.5)
-
Step 600
600 (this color)
#647B99
oklch(57.6% 0.054 255.2)
-
Step 700
700
#4E627D
oklch(49.1% 0.05 256)
-
Step 800
800
#405066
oklch(42.7% 0.042 256.4)
-
Step 900
900
#364353
oklch(37.8% 0.032 253.8)
-
Step 950
950
#202730
oklch(27% 0.02 254.8)
#647B99 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) | #707C9A | 0.017 |
| Deuteranopia (no green cones) | #6A7798 | 0.013 |
| Tritanopia (no blue cones) | #548285 | 0.048 |
| Achromatopsia (no color) | #797979 | 0.054 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #647B99
#647B99
oklch(57.6% 0.054 255.2)
- #8C7555
#8C7555
oklch(57.6% 0.054 75.5)
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 #647B99, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Grey Blue #647D8E ΔE 0.020
- Stormy Blue #507B9C ΔE 0.024
- Slate Gray #708090 ΔE 0.029
- Battleship Grey #6B7C85 ΔE 0.033
- Cerulean #457B9D ΔE 0.035
- Off Blue #5684AE ΔE 0.037
- Dusty Blue #5A86AD ΔE 0.038
- Steel Grey #6F828A ΔE 0.039
Use #647B99 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.