What color is #243E40?

#243E40 is a dark low-chroma cool gray with a subtle cool cast. In RGB it is rgb(36, 62, 64), and in HSL hsl(184, 28%, 20%).

Is #243E40 accessible as text?

On white, #243E40 has a contrast ratio of 11.42:1 (passes WCAG AA for body text); on black it is 1.84:1 (fails). For text placed on #243E40, use white for the best readability.

What is the closest Tailwind color to #243E40?

The nearest Tailwind CSS token is zinc-700 (#3F3F46).

What colors go well with #243E40?

As a neutral, #243E40 pairs cleanly with white, off-white and light grays for text, and sits under accent hues like blue, violet, emerald or warm orange — use it as a dark surface or high-contrast base and let the accent carry the color.

Is #243E40 the same as CSS darkslategray?

No — #243E40 is not the CSS named color darkslategray, but darkslategray (#2F4F4F) is the closest CSS named color by perceptual color distance — it sits in a different color family, so treat it as a rough reference, not a match.

#243E40 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #243E40

Not just a swatch — here's how #243E40 works with other colors. Named schemes with #243E40 in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #243E40 Accent #A6C4BE Surface #DFDABE Secondary #9AA0A0 Anchor #1D3549

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

Nordic Calm Accent · 5 colors

Accent #243E40 Secondary #AEB4B8 Surface #F1F2F0 Support #7A94A5 Anchor #2E3236

Onyx keeps this Nordic scheme quiet — cool greys and a soft white around it, a muted-blue support and a charcoal anchor.

Tech Product Signal · 5 colors

Signal #243E40 Surface #14161A Highlight #F4F6F8 Secondary #596771 Accent #465E60

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

Vintage Leather Lead · 5 colors

Lead #243E40 Secondary #715017 Surface #E3DCC0 Accent #395143 Anchor #552340

Onyx 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 #F6F4EF Accent #243E40 Secondary #586161 Support #979286 Ink #16140F

Onyx 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 Onyx carrying the quiet middle.

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Color Lab

How #243E40 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 42/100

Neutral

Balanced temperature — flexible, sits between warm and cool schemes.

Softness 36/100

Low

Middle-weight — neither delicate nor heavy.

Depth 62/100

High

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

Naturalness 4/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 30/100

Low

A faint retro warmth without tipping into sepia.

Luxury 64/100

High

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

Brand distinctiveness 12/100

Very low

Quiet and neutral — a supporting tone, not a signature.

UI accent fit 34/100

Low

Workable accent with care around contrast.

Surface fit 53/100

Moderate

Usable as a tinted surface in measured doses.

Print safety 92/100

Very high

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #243E40

For UI

For branding

For interior

For fashion

People also use #243E40 with

Hunter Green Gunmetal Gray Bistre Platinum Dark Slate Gray

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 11.4:1. Use

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

Avoid beside #253641 — 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 #243E40 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: #243E40;
  --color-base-rgb: 36 62 64;
  --color-base-oklch: oklch(34.4% 0.032 202.0);
  --color-50: #F5F9FA;
  --color-100: #E5F0F1;
  --color-200: #CBE0E2;
  --color-300: #A6C7CA;
  --color-400: #82ADB0;
  --color-500: #629093;
  --color-600: #4F7072;
  --color-700: #3C5153;
  --color-800: #2A3637;
  --color-900: #1B2222;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  onyx: {
    50: '#F5F9FA',
    100: '#E5F0F1',
    200: '#CBE0E2',
    300: '#A6C7CA',
    400: '#82ADB0',
    500: '#629093',
    600: '#4F7072',
    700: '#3C5153',
    800: '#2A3637',
    900: '#1B2222',
  },
}

$base: #243E40;
$base-ink: #FFFFFF;
$base-50: #F5F9FA;
$base-100: #E5F0F1;
$base-200: #CBE0E2;
$base-300: #A6C7CA;
$base-400: #82ADB0;
$base-500: #629093;
$base-600: #4F7072;
$base-700: #3C5153;
$base-800: #2A3637;
$base-900: #1B2222;
$base-hover: #1D3334;
$base-subtle: #B5CDCF;

{
    "color": {
        "base": {
            "value": "#243E40",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F5F9FA",
                "type": "color"
            },
            "100": {
                "value": "#E5F0F1",
                "type": "color"
            },
            "200": {
                "value": "#CBE0E2",
                "type": "color"
            },
            "300": {
                "value": "#A6C7CA",
                "type": "color"
            },
            "400": {
                "value": "#82ADB0",
                "type": "color"
            },
            "500": {
                "value": "#629093",
                "type": "color"
            },
            "600": {
                "value": "#4F7072",
                "type": "color"
            },
            "700": {
                "value": "#3C5153",
                "type": "color"
            },
            "800": {
                "value": "#2A3637",
                "type": "color"
            },
            "900": {
                "value": "#1B2222",
                "type": "color"
            }
        }
    }
}