Inspect DarkGray (#A9A9A9) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
DarkGray
#A9A9A9
Black text reads best on this background, at 8.94:1.
DarkGray is one of the 148 CSS named colors, and resolves to #A9A9A9 in every browser. In numbers that is rgb(169, 169, 169) and hsl(0, 0%, 66%). Perceptually it is a light, near-neutral color: OKLCH puts its lightness at 73% and its chroma at 0. It carries almost no chroma, so it behaves as a neutral rather than as a hue, and belongs with the grays.
White text only reaches 2.35:1 here, so black text is the safer pairing at 8.94:1. With this little chroma it recedes, which makes it useful for borders, dividers and secondary surfaces.
The closest CSS named colors to DarkGray, measured with CIEDE2000, are Silver (#C0C0C0), LightGray (#D3D3D3), LightGrey (#D3D3D3). If DarkGray is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#A9A9A9
RGB
rgb(169, 169, 169)
HSL
hsl(0, 0%, 66%)
HWB
hwb(0 66% 34%)
CMYK
cmyk(0%, 0%, 0%, 34%)
LAB
lab(69.24 0 0)
LCH
lch(69.24 0 0)
OKLCH
oklch(73.48% 0 0)
WCAG asks for 4.5:1 between body text and its background. On #A9A9A9 white text measures 2.35:1 and black text 8.94:1, so black clears it and white does not.
White text on DarkGray
WCAG 2.2
2.35:1
APCA
Lc 51
Fails AA body text
Fails AAA body text
Fails AA large text
Black text on DarkGray
WCAG 2.2
8.94:1
APCA
Lc 57
Passes AA body text
Passes AAA body text
Passes AA large text
Check DarkGray against any other color in the contrast checker.
DarkGray sits at 73% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #F8F8F8 and down to #060606, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#B8B8B8
20% lighter
#C8C8C8
40% lighter
#D8D8D8
60% lighter
#E8E8E8
80% lighter
#F8F8F8
100% lighter
#848484
20% darker
#606060
40% darker
#3F3F3F
60% darker
#202020
80% darker
#060606
100% darker
Build a full accessible scale from #A9A9A9 in the shade generator.
DarkGray barely moves under any of the four common forms of color blindness, the largest shift being 0 CIEDE2000 units under protanopia. It stays recognizable, though it still should not be the only thing carrying meaning.
Protanopia
#A9A9A9
Deuteranopia
#A9A9A9
Tritanopia
#A9A9A9
Achromatopsia
#A9A9A9
The nearest CSS keywords to #A9A9A9, ranked by perceptual distance rather than by how close their hex digits happen to look.