#5B8399
Closest named color: Grey Blue (#647D8E). oklch(58.9% 0.056 233), rgb(91, 131, 153).
Aa
Black text reads best on this color (5.15:1).
About this color
#5B8399 is a medium-dark, muted blue. In OKLCH its lightness is 59%, its chroma 0.056 and its hue 233°. 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 5.15:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | muted (0.056) |
| Temperature | cool |
| Nearest name | Grey Blue (#647D8E) |
| Black text | 5.15:1 |
| White text | 4.07:1 |
Values
| HEX | #5B8399 |
| RGB | rgb(91, 131, 153) |
| HSL | hsl(201, 25%, 48%) |
| OKLCH | oklch(58.9% 0.056 233) |
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 #5B8399 | 4.07:1 | AA large text | Lc -73.4 | Content text, not long reading |
| Black text on #5B8399 | 5.15:1 | AA | Lc 36.2 | Non-text elements, placeholder text |
| #5B8399 text on white | 4.07:1 | AA large text | Lc 67.9 | Content text, not long reading |
| #5B8399 text on black | 5.15:1 | AA | Lc -33.8 | 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
#F3F6F7
oklch(97.1% 0.003 219.5)
-
Step 100
100
#E5EBEE
oklch(93.6% 0.008 228.9)
-
Step 200
200
#D1DBE1
oklch(88.6% 0.014 233.8)
-
Step 300
300
#B1C4CE
oklch(80.9% 0.025 230.5)
-
Step 400
400
#88A5B6
oklch(70.6% 0.041 233.9)
-
Step 500
500
#6A8FA4
oklch(63% 0.052 233.5)
-
Step 600
600 (this color)
#5B8399
oklch(58.9% 0.056 233)
-
Step 700
700
#42667A
oklch(49.1% 0.052 233.6)
-
Step 800
800
#375363
oklch(42.7% 0.043 234.2)
-
Step 900
900
#304551
oklch(37.8% 0.033 233.9)
-
Step 950
950
#1C282F
oklch(26.9% 0.021 234.2)
#5B8399 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) | #79829A | 0.038 |
| Deuteranopia (no green cones) | #707B99 | 0.033 |
| Tritanopia (no blue cones) | #44898A | 0.041 |
| Achromatopsia (no color) | #7E7E7E | 0.056 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5B8399
#5B8399
oklch(58.9% 0.056 233)
- #98745E
#98745E
oklch(58.9% 0.056 52.8)
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 #5B8399, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Grey Blue #647D8E ΔE 0.021
- Slate Gray #708090 ΔE 0.027
- Stormy Blue #507B9C ΔE 0.030
- Dusty Blue #5A86AD ΔE 0.030
- Steel Grey #6F828A ΔE 0.031
- Steel #738595 ΔE 0.032
- Off Blue #5684AE ΔE 0.032
- Battleship Grey #6B7C85 ΔE 0.034
Use #5B8399 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.