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Calm Cadet

#639f9c
Notes

Calm Cadet (#639F9C) is a true cyan with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (177°, 24%, 51%) places it in the muted band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. For a confident two-color system, pair it with its complementary red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#639f9c
RGB
rgb(99, 159, 156)
HSL
hsl(177, 24%, 51%)
HWB
hwb(177 39% 38%)
OKLCH
oklch(66.1% 0.063 191.7)
P3
color(display-p3 0.4419 0.6175 0.6097)
HSV
hsv(177, 38%, 62%)
LAB
lab(61.52% -20.14 -4.59)
LCH
lch(61.52% 20.66 192.85)
CMYK
cmyk(38%, 0%, 2%, 38%)

Etymology

Calm
adjective

Latin calma, heat of the day — paradoxically drifted in Italian to mean stillness. Used as a color modifier since the seventeenth century for hues that read as untroubled. Calm blue, calm gray: moderate saturation combined with optical quiet. Sits at the crisp-bucket near quiet and steady.

Cadet
noun

A pale gray-blue named for the dress uniform of military cadets — particularly the West Point cadet uniform and the British Royal Military College's traditional grays. The color refers to a cadet-uniform fabric: a soft, slightly muted gray-blue with the matte finish of regulation serge wool. Cooler than slate, warmer than steel, with the institutional weight of pre-officer formal dress.

Closest matches

The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.

Variations

Click any swatch to explore

Harmonies

Accessibility

Color-vision simulation

How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.

#639f9c
Original
#98999c
Protanopia
#8e919d
Deuteranopia
#4ba29e
Tritanopia
#929292
Achromatopsia
WCAG contrast

The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AA Largeon White
3.01:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
6.97:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##639F9C
Display P3
Display P3
color(display-p3 0.4419 0.6175 0.6097)
Inside sRGBOKLCH chroma 0.063

This color sits well within the sRGB cube. P3 and sRGB share the gray axis and most desaturated tones, so a P3 display renders this identically to an sRGB display.

Related Colors

Canvas