What color is #243F78?

#243F78 is a dark blue. In RGB it is rgb(36, 63, 120), and in HSL hsl(221, 54%, 31%).

Is #243F78 accessible as text?

On white, #243F78 has a contrast ratio of 10.21:1 (passes WCAG AA for body text); on black it is 2.06:1 (fails). For text placed on #243F78, use white for the best readability.

What is the closest Tailwind color to #243F78?

The nearest Tailwind CSS token is sky-900 (#024A70).

What colors go well with #243F78?

#243F78 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #7A5F24. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #243F78 below.

Is #243F78 good for buttons?

#243F78 works well for buttons and highlights, but use white text on #243F78 — black text only reaches 2.06:1, below the 4.5:1 needed for normal-size labels.

Is #243F78 the same as CSS darkslateblue?

No — #243F78 is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#243F78 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #243F78

Not just a swatch — here's how #243F78 works with other colors. Named schemes with #243F78 in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #243F78 Accent #A5C4C1 Surface #DDDBBF Secondary #9AA0A1 Anchor #21344A

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

Luxury Packaging Feature · 5 colors

Feature #243F78 Anchor #141210 Accent #ACAE53 Secondary #242933 Surface #F0EEE3

Classic Blue carries the depth in this luxury scheme, offset by a brass accent and near-black and held together by a deep neutral and an off-white surface.

Moody Editorial Color · 5 colors

Color #243F78 Anchor #2A2A2E Secondary #6E6E74 Surface #E9E7DA Accent #1F1E45

Classic Blue adds the colour to this moody editorial scheme — charcoal and a mid-grey around it, a bone highlight, and a muted jewel accent drawn from Classic Blue.

Vintage Leather Lead · 5 colors

Lead #243F78 Secondary #7F4536 Surface #EED7C2 Accent #375246 Anchor #57223A

Classic 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.

Minimal Editorial Surface · 5 colors

Surface #F8F4EF Accent #243F78 Secondary #5E697E Support #9D8F88 Ink #18140F

Classic 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 Classic Blue carrying the quiet middle.

Build a working theme in the generator →

Color Lab

How #243F78 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 62/100

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 43/100

Moderate

A faint retro warmth without tipping into sepia.

Luxury 68/100

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 64/100

High

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

Surface fit 29/100

Low

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

Print safety 81/100

Very high

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #243F78

For UI

For branding

For interior

For fashion

People also use #243F78 with

Dark Cyan Indigo Raw Umber 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 10.2:1. Use

Subtle surface Use #CED7E9 for cards and hover fills. Tint 80

Avoid beside #26247A — 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 #243F78 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: #243F78;
  --color-base-rgb: 36 63 120;
  --color-base-oklch: oklch(37.9% 0.103 263.3);
  --color-50: #F3F6FC;
  --color-100: #DFE6F6;
  --color-200: #C0CEEC;
  --color-300: #95ABDA;
  --color-400: #6C89C6;
  --color-500: #4B69AA;
  --color-600: #3F5583;
  --color-700: #323F5D;
  --color-800: #232C3D;
  --color-900: #171C26;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  classic-blue: {
    50: '#F3F6FC',
    100: '#DFE6F6',
    200: '#C0CEEC',
    300: '#95ABDA',
    400: '#6C89C6',
    500: '#4B69AA',
    600: '#3F5583',
    700: '#323F5D',
    800: '#232C3D',
    900: '#171C26',
  },
}

$base: #243F78;
$base-ink: #FFFFFF;
$base-50: #F3F6FC;
$base-100: #DFE6F6;
$base-200: #C0CEEC;
$base-300: #95ABDA;
$base-400: #6C89C6;
$base-500: #4B69AA;
$base-600: #3F5583;
$base-700: #323F5D;
$base-800: #232C3D;
$base-900: #171C26;
$base-hover: #1D3361;
$base-subtle: #B5C2E0;

{
    "color": {
        "base": {
            "value": "#243F78",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F3F6FC",
                "type": "color"
            },
            "100": {
                "value": "#DFE6F6",
                "type": "color"
            },
            "200": {
                "value": "#C0CEEC",
                "type": "color"
            },
            "300": {
                "value": "#95ABDA",
                "type": "color"
            },
            "400": {
                "value": "#6C89C6",
                "type": "color"
            },
            "500": {
                "value": "#4B69AA",
                "type": "color"
            },
            "600": {
                "value": "#3F5583",
                "type": "color"
            },
            "700": {
                "value": "#323F5D",
                "type": "color"
            },
            "800": {
                "value": "#232C3D",
                "type": "color"
            },
            "900": {
                "value": "#171C26",
                "type": "color"
            }
        }
    }
}

Palettes built on #243F78

Color Lab

Pairs with #243F78

UI roles & guardrails

In real applications

Scales

Every model

Export