Inspect MediumSlateBlue (#7B68EE) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
MediumSlateBlue
#7B68EE
Black text reads best on this background, at 5.06:1.
MediumSlateBlue is one of the 148 CSS named colors, and resolves to #7B68EE in every browser. In numbers that is rgb(123, 104, 238) and hsl(249, 80%, 67%). Perceptually it is a mid-toned, vivid color: OKLCH puts its lightness at 60% and its chroma at 0.194. It sits in the purples at 285 degrees of OKLCH hue, and reads as a cool color.
White text only reaches 4.15:1 here, so black text is the safer pairing at 5.06:1. At this chroma it is loud enough to be an accent or a call to action, but it will fight anything else vivid placed next to it.
The closest CSS named colors to MediumSlateBlue, measured with CIEDE2000, are MediumPurple (#9370DB), SlateBlue (#6A5ACD), RoyalBlue (#4169E1). If MediumSlateBlue is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#7B68EE
RGB
rgb(123, 104, 238)
HSL
hsl(249, 80%, 67%)
HWB
hwb(249 41% 7%)
CMYK
cmyk(48%, 56%, 0%, 7%)
LAB
lab(51.28 33.84 -66.48)
LCH
lch(51.28 74.59 296.98)
OKLCH
oklch(60.45% 0.1939 285.5)
WCAG asks for 4.5:1 between body text and its background. On #7B68EE white text measures 4.15:1 and black text 5.06:1, so black clears it and white does not.
White text on MediumSlateBlue
WCAG 2.2
4.15:1
APCA
Lc 73
Fails AA body text
Fails AAA body text
Passes AA large text
Black text on MediumSlateBlue
WCAG 2.2
5.06:1
APCA
Lc 35
Passes AA body text
Fails AAA body text
Passes AA large text
Check MediumSlateBlue against any other color in the contrast checker.
MediumSlateBlue sits at 60% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #F8F8FF and down to #06001F, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#9083FF
20% lighter
#A8A2FF
40% lighter
#C1C0FF
60% lighter
#DCDCFF
80% lighter
#F8F8FF
100% lighter
#6149CD
20% darker
#4928AC
40% darker
#320087
60% darker
#1B0050
80% darker
#06001F
100% darker
Build a full accessible scale from #7B68EE in the shade generator.
Hues rotated around #7B68EE in OKLCH, then pulled back into the sRGB gamut. Each swatch is labelled with the nearest CSS named color so you have a keyword to start from.
MediumSlateBlue sits at 285 degrees. Rotating it a half turn lands on 105 degrees, the hue directly opposite. It is the strongest pairing you can make without changing lightness, and the one most likely to vibrate if you use both at full chroma.
The neighbors of MediumSlateBlue at 255 and 315 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
285, 45 and 165 degrees divide the wheel into thirds. Balanced enough to carry a whole palette without one color dominating the other two.
Instead of the complement at 105 degrees, this pair flanks it at 75 and 135. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around MediumSlateBlue on the color wheel.
The biggest shift is under achromatopsia, where #7B68EE reads as #767676, 28.4 CIEDE2000 units away. If MediumSlateBlue is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#4F77F5
Deuteranopia
#5074EA
Tritanopia
#687A91
Achromatopsia
#767676
The nearest CSS keywords to #7B68EE, ranked by perceptual distance rather than by how close their hex digits happen to look.