Grey Blue #647D8E
Grey Blue is a medium-dark, muted blue with hex code #647D8E and RGB rgb(100, 125, 142).
Aa
Black text reads best on this color (4.86:1).
About this color
#647D8E is a medium-dark, muted blue. In OKLCH its lightness is 58%, its chroma 0.039 and its hue 238°. Its hue sits on the cool side of the wheel. It is the named color Grey Blue. Black text reads best on it, at 4.86:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | muted (0.039) |
| Temperature | cool |
| Nearest name | Grey Blue |
| Black text | 4.86:1 |
| White text | 4.31:1 |
Colors that go with Grey Blue
Matches found by rotating Grey Blue around the OKLCH hue wheel, each labelled with the closest name in our list.
Complementary
The opposite hue (180°).
Analogous
Neighbouring hues, 30° either side.
Triadic
Three hues spaced 120° apart.
Color palettes with Grey Blue
Curated color palettes that contain a color within ΔE 0.06 (OKLab) of Grey Blue, closest first.
Similar named colors
The eight named colors closest to Grey Blue, with their ΔE distance.
- Battleship Grey #6B7C85 ΔE 0.015
- Slate Gray #708090 ΔE 0.019
- Steel Grey #6F828A ΔE 0.024
- Battleship Gray #6C757D ΔE 0.029
- Steel #738595 ΔE 0.033
- Stormy Blue #507B9C ΔE 0.033
- Metallic Blue #4F738E ΔE 0.042
- Lavender Gray #7E7F9A ΔE 0.042
More about Grey Blue
How to make Grey Blue
A starting recipe from common paint colors, found with a spectral paint model (the color mixer’s paint mode). Real pigments vary, so mix a small test batch and adjust.
- 2 parts gray
- 1 part blue
Recipe result: #5A7D8F, a difference of ΔE 0.013 from Grey Blue. That is very close: most people will not see the difference.
Codes for Grey Blue in every format
| HEX | #647D8E |
| RGB | rgb(100, 125, 142) |
| HSL | hsl(204, 17%, 47%) |
| OKLCH | oklch(57.6% 0.039 238.1) |
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 #647D8E | 4.31:1 | AA large text | Lc -75.3 | Fine for body text |
| Black text on #647D8E | 4.86:1 | AA | Lc 34.2 | Non-text elements, placeholder text |
| #647D8E text on white | 4.31:1 | AA large text | Lc 69.9 | Content text, not long reading |
| #647D8E text on black | 4.86:1 | AA | Lc -31.8 | Non-text elements, placeholder text |
Shades and tints of Grey Blue
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
#F4F6F7
oklch(97.2% 0.003 228.8)
-
Step 100
100
#E7EAED
oklch(93.6% 0.005 247.9)
-
Step 200
200
#D3DADF
oklch(88.4% 0.01 238.5)
-
Step 300
300
#B7C3CB
oklch(81% 0.017 236.7)
-
Step 400
400
#91A4B0
oklch(70.8% 0.028 235.5)
-
Step 500
500
#768D9D
oklch(63.1% 0.036 238.5)
-
Step 600
600 (this color)
#647D8E
oklch(57.6% 0.039 238.1)
-
Step 700
700
#4E6473
oklch(49.1% 0.036 238.3)
-
Step 800
800
#40525E
oklch(42.8% 0.03 237.6)
-
Step 900
900
#36444D
oklch(37.8% 0.024 236.5)
-
Step 950
950
#20282D
oklch(27.1% 0.015 235.5)
Grey Blue 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) | #767C8F | 0.025 |
| Deuteranopia (no green cones) | #70788E | 0.021 |
| Tritanopia (no blue cones) | #578182 | 0.030 |
| Achromatopsia (no color) | #7A7A7A | 0.039 |
Use Grey Blue 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.