What color is #403DA5?

#403DA5 is a medium blue-violet. In RGB it is rgb(64, 61, 165), and in HSL hsl(242, 46%, 44%).

Is #403DA5 accessible as text?

On white, #403DA5 has a contrast ratio of 8.65:1 (passes WCAG AA for body text); on black it is 2.43:1 (fails). For text placed on #403DA5, use white for the best readability.

What is the closest Tailwind color to #403DA5?

The nearest Tailwind CSS token is indigo-800 (#372AAC).

What colors go well with #403DA5?

#403DA5 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #A0A43D. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #403DA5 below.

Is #403DA5 good for buttons?

#403DA5 works well for buttons and highlights, but use white text on #403DA5 — black text only reaches 2.43:1, below the 4.5:1 needed for normal-size labels.

Is #403DA5 the same as CSS darkslateblue?

No — #403DA5 is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#403DA5 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #403DA5

Not just a swatch — here's how #403DA5 works with other colors. Named schemes with #403DA5 in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #403DA5 Accent #A5C4C2 Surface #EAD5BF Secondary #9AA0A1 Anchor #22344A

Dark 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 #403DA5 Secondary #7F4534 Surface #EED7C2 Accent #365247 Anchor #582239

Dark 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 #403DA5 Anchor #3B2923 Surface #F3E1D2 Accent #769F7B Secondary #3C3734

Dark 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 #403DA5 Surface #F6E5D8 Anchor #5B2142 Accent #E5C2C9 Secondary #322B2F

Dark 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 #403DA5 Secondary #6F7499 Support #9D9088 Ink #18140F

Dark 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 Dark Slate Blue carrying the quiet middle.

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Color Lab

How #403DA5 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 18/100

Cool

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

Softness 31/100

Low

Firm and assertive — carries weight and contrast.

Depth 60/100

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 33/100

Low

A faint retro warmth without tipping into sepia.

Luxury 60/100

Moderate

Restrained and premium — deep, quiet, high-end packaging and fashion.

Brand distinctiveness 44/100

Moderate

Recognisable but shares space with nearby hues.

UI accent fit 82/100

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 #403DA5

For UI

For branding

For interior

For fashion

People also use #403DA5 with

Steel Blue Grape Citron Gainsboro Prussian Blue

UI roles & guardrails

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

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 8.6:1. Use

Subtle surface Use #DAD9EC for cards and hover fills. Tint 80

Avoid beside #623DA4 — 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 #403DA5 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: #403DA5;
  --color-base-rgb: 64 61 165;
  --color-base-oklch: oklch(42.8% 0.162 278.3);
  --color-50: #F4F3FB;
  --color-100: #E1E1F5;
  --color-200: #C5C4E9;
  --color-300: #9C9AD5;
  --color-400: #7573BF;
  --color-500: #5552A3;
  --color-600: #46447E;
  --color-700: #36355A;
  --color-800: #26253C;
  --color-900: #191825;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  dark-slate-blue: {
    50: '#F4F3FB',
    100: '#E1E1F5',
    200: '#C5C4E9',
    300: '#9C9AD5',
    400: '#7573BF',
    500: '#5552A3',
    600: '#46447E',
    700: '#36355A',
    800: '#26253C',
    900: '#191825',
  },
}

$base: #403DA5;
$base-ink: #FFFFFF;
$base-50: #F4F3FB;
$base-100: #E1E1F5;
$base-200: #C5C4E9;
$base-300: #9C9AD5;
$base-400: #7573BF;
$base-500: #5552A3;
$base-600: #46447E;
$base-700: #36355A;
$base-800: #26253C;
$base-900: #191825;
$base-hover: #333083;
$base-subtle: #C6C5E3;

{
    "color": {
        "base": {
            "value": "#403DA5",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F4F3FB",
                "type": "color"
            },
            "100": {
                "value": "#E1E1F5",
                "type": "color"
            },
            "200": {
                "value": "#C5C4E9",
                "type": "color"
            },
            "300": {
                "value": "#9C9AD5",
                "type": "color"
            },
            "400": {
                "value": "#7573BF",
                "type": "color"
            },
            "500": {
                "value": "#5552A3",
                "type": "color"
            },
            "600": {
                "value": "#46447E",
                "type": "color"
            },
            "700": {
                "value": "#36355A",
                "type": "color"
            },
            "800": {
                "value": "#26253C",
                "type": "color"
            },
            "900": {
                "value": "#191825",
                "type": "color"
            }
        }
    }
}

Palettes built on #403DA5

Color Lab

Pairs with #403DA5

UI roles & guardrails

In real applications

Scales

Every model

Export