Inspect WhiteSmoke (#F5F5F5) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
WhiteSmoke
#F5F5F5
Black text reads best on this background, at 19.26:1.
WhiteSmoke is one of the 148 CSS named colors, and resolves to #F5F5F5 in every browser. In numbers that is rgb(245, 245, 245) and hsl(0, 0%, 96%). Perceptually it is a very light, near-neutral color: OKLCH puts its lightness at 97% 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 off-whites.
White text only reaches 1.09:1 here, so black text is the safer pairing at 19.26:1. Because it is this light, WhiteSmoke works best as a page or card background with dark text over it.
The closest CSS named colors to WhiteSmoke, measured with CIEDE2000, are White (#FFFFFF), Snow (#FFFAFA), GhostWhite (#F8F8FF). If WhiteSmoke is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#F5F5F5
RGB
rgb(245, 245, 245)
HSL
hsl(0, 0%, 96%)
HWB
hwb(0 96% 4%)
CMYK
cmyk(0%, 0%, 0%, 4%)
LAB
lab(96.54 0 0)
LCH
lch(96.54 0 0)
OKLCH
oklch(97.02% 0 0)
WCAG asks for 4.5:1 between body text and its background. On #F5F5F5 white text measures 1.09:1 and black text 19.26:1, so black clears it and white does not.
White text on WhiteSmoke
WCAG 2.2
1.09:1
APCA
Lc 0
Fails AA body text
Fails AAA body text
Fails AA large text
Black text on WhiteSmoke
WCAG 2.2
19.26:1
APCA
Lc 100
Passes AA body text
Passes AAA body text
Passes AA large text
Check WhiteSmoke against any other color in the contrast checker.
WhiteSmoke sits at 97% OKLCH lightness. Holding its hue and chroma and moving only that value carries it down to #060606, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#BEBEBE
20% darker
#898989
40% darker
#585858
60% darker
#2B2B2B
80% darker
#060606
100% darker
Build a full accessible scale from #F5F5F5 in the shade generator.
WhiteSmoke 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
#F5F5F5
Deuteranopia
#F5F5F5
Tritanopia
#F5F5F5
Achromatopsia
#F5F5F5
The nearest CSS keywords to #F5F5F5, ranked by perceptual distance rather than by how close their hex digits happen to look.