What color is #043EA9?

#043EA9 is a dark, vivid blue. In RGB it is rgb(4, 62, 169), and in HSL hsl(219, 95%, 34%).

Is #043EA9 accessible as text?

On white, #043EA9 has a contrast ratio of 9.26:1 (passes WCAG AA for body text); on black it is 2.27:1 (fails). For text placed on #043EA9, use white for the best readability.

What is the closest Tailwind color to #043EA9?

The nearest Tailwind CSS token is blue-800 (#193CB8).

What colors go well with #043EA9?

#043EA9 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #A96F04. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #043EA9 below.

Is #043EA9 good for buttons?

#043EA9 works well for buttons and highlights, but use white text on #043EA9 — black text only reaches 2.27:1, below the 4.5:1 needed for normal-size labels.

Is #043EA9 the same as CSS darkslateblue?

No — #043EA9 is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#043EA9 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #043EA9

Not just a swatch — here's how #043EA9 works with other colors. Named schemes with #043EA9 in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #043EA9 Accent #A5C4C1 Surface #DDDBBF Secondary #9AA0A1 Anchor #21344A

Cobalt 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 #043EA9 Surface #14161A Highlight #F4F6F8 Secondary #5A6672 Accent #3366C7

Cobalt 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 Cobalt Blue.

Vintage Leather Lead · 5 colors

Lead #043EA9 Secondary #7F4536 Surface #E1DDC1 Accent #375246 Anchor #57223A

Cobalt 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 #043EA9 Surface #F6E5D8 Anchor #5A2144 Accent #E4C2CA Secondary #322B2F

Cobalt 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 #043EA9 Secondary #5D7297 Support #9D8F88 Ink #18140F

Cobalt 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 Cobalt Blue carrying the quiet middle.

Build a working theme in the generator →

Color Lab

How #043EA9 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 8/100

Cool

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

Softness 28/100

Low

Firm and assertive — carries weight and contrast.

Depth 62/100

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 25/100

Low

A faint retro warmth without tipping into sepia.

Luxury 60/100

High

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

Brand distinctiveness 49/100

Moderate

Recognisable but shares space with nearby hues.

UI accent fit 73/100

High

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

Surface fit 13/100

Very low

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

Print safety 66/100

High

Prints close, with a slight loss of vibrancy.

Pairs with #043EA9

For UI

For branding

For interior

For fashion

People also use #043EA9 with

Lagoon Blue Zaffre Olive Brown Gainsboro Charcoal

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 9.3:1. Use

Subtle surface Use #C6D6F4 for cards and hover fills. Tint 80

Avoid beside #0407A9 — 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 #043EA9 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: #043EA9;
  --color-base-rgb: 4 62 169;
  --color-base-oklch: oklch(40.9% 0.180 261.8);
  --color-50: #F0F5FE;
  --color-100: #D8E5FD;
  --color-200: #B1CBFC;
  --color-300: #7AA5F5;
  --color-400: #4A81E8;
  --color-500: #2761CE;
  --color-600: #264F9C;
  --color-700: #213C6E;
  --color-800: #1A2A47;
  --color-900: #121B2B;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cobalt-blue: {
    50: '#F0F5FE',
    100: '#D8E5FD',
    200: '#B1CBFC',
    300: '#7AA5F5',
    400: '#4A81E8',
    500: '#2761CE',
    600: '#264F9C',
    700: '#213C6E',
    800: '#1A2A47',
    900: '#121B2B',
  },
}

$base: #043EA9;
$base-ink: #FFFFFF;
$base-50: #F0F5FE;
$base-100: #D8E5FD;
$base-200: #B1CBFC;
$base-300: #7AA5F5;
$base-400: #4A81E8;
$base-500: #2761CE;
$base-600: #264F9C;
$base-700: #213C6E;
$base-800: #1A2A47;
$base-900: #121B2B;
$base-hover: #033287;
$base-subtle: #A8C2F1;

{
    "color": {
        "base": {
            "value": "#043EA9",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F0F5FE",
                "type": "color"
            },
            "100": {
                "value": "#D8E5FD",
                "type": "color"
            },
            "200": {
                "value": "#B1CBFC",
                "type": "color"
            },
            "300": {
                "value": "#7AA5F5",
                "type": "color"
            },
            "400": {
                "value": "#4A81E8",
                "type": "color"
            },
            "500": {
                "value": "#2761CE",
                "type": "color"
            },
            "600": {
                "value": "#264F9C",
                "type": "color"
            },
            "700": {
                "value": "#213C6E",
                "type": "color"
            },
            "800": {
                "value": "#1A2A47",
                "type": "color"
            },
            "900": {
                "value": "#121B2B",
                "type": "color"
            }
        }
    }
}

Palettes built on #043EA9

Color Lab

Pairs with #043EA9

UI roles & guardrails

In real applications

Scales

Every model

Export