What color is #665BD0?

#665BD0 is a medium indigo. In RGB it is rgb(102, 91, 208), and in HSL hsl(246, 55%, 59%).

Is #665BD0 accessible as text?

On white, #665BD0 has a contrast ratio of 5.29:1 (passes WCAG AA for body text); on black it is 3.97:1 (fails). For text placed on #665BD0, use white for the best readability.

What is the closest Tailwind color to #665BD0?

The nearest Tailwind CSS token is indigo-500 (#615FFF).

What colors go well with #665BD0?

#665BD0 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #C4D05D. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #665BD0 below.

Is #665BD0 good for buttons?

#665BD0 works well for buttons and highlights, but use white text on #665BD0 — black text only reaches 3.97:1, below the 4.5:1 needed for normal-size labels.

Is #665BD0 the same as CSS slateblue?

No — #665BD0 is not the CSS named color slateblue, but slateblue (#6A5ACD) is the closest CSS named color.

#665BD0 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #665BD0

Not just a swatch — here's how #665BD0 works with other colors. Named schemes with #665BD0 in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #665BD0 Accent #A5C4C3 Surface #EAD5BF Secondary #9AA0A1 Anchor #22334A

Slate Blue opens this coastal palette with sea-glass and warm sand alongside it, grounded by driftwood grey and a deep-navy anchor.

Vintage Leather Lead · 5 colors

Lead #665BD0 Secondary #7F4533 Surface #EDD7C2 Accent #365247 Anchor #582238

Slate Blue plays the worn-leather lead, deepened by saddle brown and an oxblood anchor, softened by aged cream and cooled by a muted forest green.

Modern Café Dominant · 5 colors

Dominant #665BD0 Anchor #3B2923 Surface #F3E1D2 Accent #759F7C Secondary #3C3734

Slate Blue anchors this café scheme as the warm mid-tone, lifted by latte cream and a muted sage accent and grounded by espresso brown and a warm charcoal.

Berry & Cream Lead · 5 colors

Lead #665BD0 Surface #F5E5D7 Anchor #5B2142 Accent #E5C2C9 Secondary #332B2F

Slate Blue sits between cream and a deep berry here, softened by a blush accent and grounded by charcoal.

Minimal Editorial Surface · 5 colors

Surface #F8F4EF Accent #665BD0 Secondary #9495BF Support #9D9088 Ink #18140F

Slate Blue is the single accent in this high-contrast editorial system — set on near-white paper against near-black ink, with a warm grey and a desaturated tint of Slate Blue carrying the quiet middle.

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Color Lab

How #665BD0 actually behaves in design work — read from its OKLCH lightness, chroma and hue, not just its raw numbers. Ten signals to help you decide where this color earns its place.

Warmth 20/100

Cool

Reads cool and recessive — calming, technical, good for trust-led UI.

Softness 37/100

Low

Middle-weight — neither delicate nor heavy.

Depth 48/100

Moderate

Mid depth — usable as an accent or a muted ground.

Naturalness 0/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 36/100

Low

A faint retro warmth without tipping into sepia.

Luxury 49/100

Moderate

Understated — leans refined without going austere.

Brand distinctiveness 47/100

Moderate

Recognisable but shares space with nearby hues.

UI accent fit 95/100

Very high

Strong interactive accent — visible and can carry a legible label.

Surface fit 12/100

Very low

Too saturated or mid-toned for big areas — keep it to accents.

Print safety 75/100

High

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #665BD0

For UI

For branding

For interior

For fashion

People also use #665BD0 with

Iceberg Medium Orchid Citrine Gainsboro Prussian Blue

UI roles & guardrails

Primary action Safe as a filled button with white label. AA

Body text Passes on white at 16px and above. Pass

Large display Fine for headings 24px+ on white. Pass

Background Pair with white text at 5.3:1. Use

Subtle surface Use #E3E2F2 for cards and hover fills. Tint 80

Avoid beside #8F5DD0 — the hue gap is too small to read as intentional. Clash

In real applications

Not a swatch to memorise — a color to build with. Here is #665BD0 at work across the surfaces designers actually ship.

Website / UI

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Dashboard

Revenue

$48.2k ▲ 12%

Brand

AVELINE

Studio

Poster

Nov 14 · 8PM

NIGHT
MARKET

Packaging

BLOOM

Botanical Wash

250 ml

Interior

Every model

Export

:root {
  --color-base: #665BD0;
  --color-base-rgb: 102 91 208;
  --color-base-oklch: oklch(54.4% 0.174 283.2);
  --color-50: #F4F3FC;
  --color-100: #E1DFF6;
  --color-200: #C4C0ED;
  --color-300: #9B94DB;
  --color-400: #756BC7;
  --color-500: #544AAB;
  --color-600: #463F83;
  --color-700: #36315E;
  --color-800: #26233E;
  --color-900: #191726;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  slate-blue: {
    50: '#F4F3FC',
    100: '#E1DFF6',
    200: '#C4C0ED',
    300: '#9B94DB',
    400: '#756BC7',
    500: '#544AAB',
    600: '#463F83',
    700: '#36315E',
    800: '#26233E',
    900: '#191726',
  },
}

$base: #665BD0;
$base-ink: #FFFFFF;
$base-50: #F4F3FC;
$base-100: #E1DFF6;
$base-200: #C4C0ED;
$base-300: #9B94DB;
$base-400: #756BC7;
$base-500: #544AAB;
$base-600: #463F83;
$base-700: #36315E;
$base-800: #26233E;
$base-900: #191726;
$base-hover: #4336BB;
$base-subtle: #D5D3ED;

{
    "color": {
        "base": {
            "value": "#665BD0",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F4F3FC",
                "type": "color"
            },
            "100": {
                "value": "#E1DFF6",
                "type": "color"
            },
            "200": {
                "value": "#C4C0ED",
                "type": "color"
            },
            "300": {
                "value": "#9B94DB",
                "type": "color"
            },
            "400": {
                "value": "#756BC7",
                "type": "color"
            },
            "500": {
                "value": "#544AAB",
                "type": "color"
            },
            "600": {
                "value": "#463F83",
                "type": "color"
            },
            "700": {
                "value": "#36315E",
                "type": "color"
            },
            "800": {
                "value": "#26233E",
                "type": "color"
            },
            "900": {
                "value": "#191726",
                "type": "color"
            }
        }
    }
}

Palettes built on #665BD0

Color Lab

Pairs with #665BD0

UI roles & guardrails

In real applications

Scales

Every model

Export