Palettes / Colors / #646BBB

#646BBB — Muted Blue

#646BBB is a blue color we call Muted Blue, closest to the named color SlateBlue (#6A5ACD). It belongs to the blue family.

Color name

Closest CSS keyword: slateblue (#6A5ACD) — not an exact match. CSS slateblue gives you #6A5ACD, a different color; use #646BBB when you need this exact shade.

Sources: common names follow widely used color-name references; CSS keywords and their hex values follow the CSS Color specification.

#646BBB is a cool blue color associated with trust, calm and professionalism. It sits comfortably in the middle: usable for large areas in soft schemes, or as a supporting color beside something stronger.

Its strongest partner is its complement #BBB363; it also sits naturally between #6396BB and #8863BB. In the palettes below you can see it working alongside real color combinations from our collection.

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Color values

RGB & CMYK percentages

Red 39% · Green 42% · Blue 73%

Cyan 47% · Magenta 43% · Yellow 0% · Key 27%

CMYK values are unprofiled approximations for screen reference — not a print-proofing guarantee.

Previews

CSS code for #646BBB

.text { color: #646BBB; }
.background { background-color: #646BBB; }
.border { border: 3px solid #646BBB; }
.text-rgb { color: rgb(100, 107, 187); }
.text-hsl { color: hsl(235, 39%, 56%); }
.text-shadow-hex { text-shadow: 4px 4px 2px #646BBB; }
.text-shadow-rgba { text-shadow: 4px 4px 2px rgba(100, 107, 187, 0.8); }
.box-shadow-hex { box-shadow: 1px 1px 3px 2px #646BBB; }
.box-shadow-rgba { box-shadow: 1px 1px 3px 2px rgba(100, 107, 187, 0.8); }

HTML: <p style="color:#646BBB">Text here</p> · <div style="background-color:#646BBB">Div content here</div>

Shades of #646BBB

Tints of #646BBB

Tones of #646BBB

Color harmonies

Complementary — #BBB363:

Analogous:

Triadic:

Contrast & accessibility

Best text color on #646BBB: #FFFFFF.

Semi-transparent (opacity) text on #646BBB

Text set with opacity blends into the background, so its real contrast is lower than the solid ratios above. Choose a text color and an opacity to see the blended color and its true ratio:

How #646BBB looks with color blindness

Simulated with standard Machado color-vision-deficiency matrices — useful when this color carries meaning in charts, maps or interfaces:

Closest design-system colors

The nearest matches in the Tailwind CSS, Material Design and Bootstrap palettes — handy when you need a framework class instead of a raw hex:

Palettes with a similar color

These palettes use a close neighbour of #646BBB rather than the exact color:

Similar colors

The closest colors that actually appear in our palette collection — click any to open its page:

Browse neighbouring colors

← #646BBA  ·  #646BBC →

Frequently asked questions

What color is #646BBB?

#646BBB is Muted Blue, a blue color (RGB 100, 107, 187). Its closest standard named color is SlateBlue.

What is the RGB and HSL of #646BBB?

#646BBB is RGB 100, 107, 187 — HSL 235°, 39%, 56% — CMYK 47%, 43%, 0%, 27%.

What colors go with #646BBB?

Its complement is #BBB363; analogous partners are #6396BB and #8863BB. It also appears in 6+ palettes in our collection.

Can I use #646BBB for text?

White text on #646BBB has a contrast ratio of 4.81:1 (passes WCAG AA); black text gives 4.36:1.