What color is #40318E?

#40318E is a dark indigo. In RGB it is rgb(64, 49, 142), and in HSL hsl(250, 49%, 37%).

Is #40318E accessible as text?

On white, #40318E has a contrast ratio of 10.25:1 (passes WCAG AA for body text); on black it is 2.05:1 (fails). For text placed on #40318E, use white for the best readability.

What is the closest Tailwind color to #40318E?

The nearest Tailwind CSS token is indigo-900 (#312C85).

What colors go well with #40318E?

#40318E pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #7D8D30. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #40318E below.

Is #40318E good for buttons?

#40318E works well for buttons and highlights, but use white text on #40318E — black text only reaches 2.05:1, below the 4.5:1 needed for normal-size labels.

Is #40318E the same as CSS darkslateblue?

No — #40318E is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#40318E Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #40318E

Not just a swatch — here's how #40318E works with other colors. Named schemes with #40318E in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #40318E Accent #A5C4C3 Surface #EAD5BF Secondary #9AA0A1 Anchor #22334A

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 #40318E Secondary #7E4533 Surface #EDD7C2 Accent #365247 Anchor #582238

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 #40318E Anchor #3B2923 Surface #F3E1D2 Accent #759F7C 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 #40318E Surface #F5E5D7 Anchor #5B2142 Accent #E5C2C8 Secondary #332B2F

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 #40318E Secondary #686788 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.

Build a working theme in the generator →

Color Lab

How #40318E 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 25/100

Cool

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

Softness 30/100

Low

Firm and assertive — carries weight and contrast.

Depth 63/100

High

Deep and grounding — anchors a layout, strong dark-mode base.

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 65/100

High

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

Brand distinctiveness 40/100

Low

Recognisable but shares space with nearby hues.

UI accent fit 70/100

High

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

Surface fit 15/100

Very low

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

Print safety 79/100

High

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #40318E

For UI

For branding

For interior

For fashion

People also use #40318E with

Lapis Lazuli Eminence Olive Drab 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 10.3:1. Use

Subtle surface Use #D7D4EA for cards and hover fills. Tint 80

Avoid beside #5E308D — 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 #40318E at work across the surfaces designers actually ship.

Website / UI

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A working theme, generated in seconds.

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: #40318E;
  --color-base-rgb: 64 49 142;
  --color-base-oklch: oklch(38.8% 0.147 284.6);
  --color-50: #F5F3FB;
  --color-100: #E4E0F5;
  --color-200: #C9C2EA;
  --color-300: #A398D7;
  --color-400: #7E70C2;
  --color-500: #5E4FA6;
  --color-600: #4D427F;
  --color-700: #3A345B;
  --color-800: #29253C;
  --color-900: #1A1825;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  dark-slate-blue: {
    50: '#F5F3FB',
    100: '#E4E0F5',
    200: '#C9C2EA',
    300: '#A398D7',
    400: '#7E70C2',
    500: '#5E4FA6',
    600: '#4D427F',
    700: '#3A345B',
    800: '#29253C',
    900: '#1A1825',
  },
}

$base: #40318E;
$base-ink: #FFFFFF;
$base-50: #F5F3FB;
$base-100: #E4E0F5;
$base-200: #C9C2EA;
$base-300: #A398D7;
$base-400: #7E70C2;
$base-500: #5E4FA6;
$base-600: #4D427F;
$base-700: #3A345B;
$base-800: #29253C;
$base-900: #1A1825;
$base-hover: #332670;
$base-subtle: #C3BDE1;

{
    "color": {
        "base": {
            "value": "#40318E",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F5F3FB",
                "type": "color"
            },
            "100": {
                "value": "#E4E0F5",
                "type": "color"
            },
            "200": {
                "value": "#C9C2EA",
                "type": "color"
            },
            "300": {
                "value": "#A398D7",
                "type": "color"
            },
            "400": {
                "value": "#7E70C2",
                "type": "color"
            },
            "500": {
                "value": "#5E4FA6",
                "type": "color"
            },
            "600": {
                "value": "#4D427F",
                "type": "color"
            },
            "700": {
                "value": "#3A345B",
                "type": "color"
            },
            "800": {
                "value": "#29253C",
                "type": "color"
            },
            "900": {
                "value": "#1A1825",
                "type": "color"
            }
        }
    }
}

Palettes built on #40318E

Color Lab

Pairs with #40318E

UI roles & guardrails

In real applications

Scales

Every model

Export