What color is #373F8A?

#373F8A is a dark blue-violet. In RGB it is rgb(55, 63, 138), and in HSL hsl(234, 43%, 38%).

Is #373F8A accessible as text?

On white, #373F8A has a contrast ratio of 9.37:1 (passes WCAG AA for body text); on black it is 2.24:1 (fails). For text placed on #373F8A, use white for the best readability.

What is the closest Tailwind color to #373F8A?

The nearest Tailwind CSS token is blue-900 (#1C398E).

What colors go well with #373F8A?

#373F8A pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #8B8237. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #373F8A below.

Is #373F8A good for buttons?

#373F8A works well for buttons and highlights, but use white text on #373F8A — black text only reaches 2.24:1, below the 4.5:1 needed for normal-size labels.

Is #373F8A the same as CSS darkslateblue?

No — #373F8A is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#373F8A Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #373F8A

Not just a swatch — here's how #373F8A works with other colors. Named schemes with #373F8A in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #373F8A Accent #A5C4C2 Surface #EAD5C0 Secondary #9AA0A1 Anchor #21344A

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

Tech Product Signal · 5 colors

Signal #373F8A Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #5863AA

Dark Slate Blue is the vivid signal in this product UI — on a near-black surface with cool white, a slate grey and a lighter tint of Dark Slate Blue.

Vintage Leather Lead · 5 colors

Lead #373F8A Secondary #7F4535 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.

Berry & Cream Lead · 5 colors

Lead #373F8A Surface #F6E5D8 Anchor #5B2143 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 #373F8A Secondary #686E89 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 #373F8A 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 24/100

Cool

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

Softness 33/100

Low

Middle-weight — neither delicate nor heavy.

Depth 60/100

High

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

Naturalness 0/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 42/100

Moderate

A faint retro warmth without tipping into sepia.

Luxury 65/100

High

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

Brand distinctiveness 33/100

Low

Recognisable but shares space with nearby hues.

UI accent fit 75/100

High

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

Surface fit 21/100

Low

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

Print safety 80/100

Very high

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #373F8A

For UI

For branding

For interior

For fashion

People also use #373F8A with

Steel Blue Rebecca Purple Olive 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 9.4:1. Use

Subtle surface Use #D6D8E9 for cards and hover fills. Tint 80

Avoid beside #4B378B — 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 #373F8A at work across the surfaces designers actually ship.

Website / UI

Northwind Sign up

Build faster.

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: #373F8A;
  --color-base-rgb: 55 63 138;
  --color-base-oklch: oklch(40.4% 0.124 274.9);
  --color-50: #F4F4FB;
  --color-100: #E1E3F4;
  --color-200: #C5C8E8;
  --color-300: #9CA1D3;
  --color-400: #757DBD;
  --color-500: #555CA0;
  --color-600: #464B7C;
  --color-700: #363A59;
  --color-800: #26283B;
  --color-900: #191A24;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  dark-slate-blue: {
    50: '#F4F4FB',
    100: '#E1E3F4',
    200: '#C5C8E8',
    300: '#9CA1D3',
    400: '#757DBD',
    500: '#555CA0',
    600: '#464B7C',
    700: '#363A59',
    800: '#26283B',
    900: '#191A24',
  },
}

$base: #373F8A;
$base-ink: #FFFFFF;
$base-50: #F4F4FB;
$base-100: #E1E3F4;
$base-200: #C5C8E8;
$base-300: #9CA1D3;
$base-400: #757DBD;
$base-500: #555CA0;
$base-600: #464B7C;
$base-700: #363A59;
$base-800: #26283B;
$base-900: #191A24;
$base-hover: #2C336F;
$base-subtle: #C0C3DF;

{
    "color": {
        "base": {
            "value": "#373F8A",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F4F4FB",
                "type": "color"
            },
            "100": {
                "value": "#E1E3F4",
                "type": "color"
            },
            "200": {
                "value": "#C5C8E8",
                "type": "color"
            },
            "300": {
                "value": "#9CA1D3",
                "type": "color"
            },
            "400": {
                "value": "#757DBD",
                "type": "color"
            },
            "500": {
                "value": "#555CA0",
                "type": "color"
            },
            "600": {
                "value": "#464B7C",
                "type": "color"
            },
            "700": {
                "value": "#363A59",
                "type": "color"
            },
            "800": {
                "value": "#26283B",
                "type": "color"
            },
            "900": {
                "value": "#191A24",
                "type": "color"
            }
        }
    }
}

Palettes built on #373F8A

Color Lab

Pairs with #373F8A

UI roles & guardrails

In real applications

Scales

Every model

Export