What color is #303E40?

#303E40 is a dark low-chroma cool gray with a subtle cool cast. In RGB it is rgb(48, 62, 64), and in HSL hsl(188, 14%, 22%).

Is #303E40 accessible as text?

On white, #303E40 has a contrast ratio of 11.12:1 (passes WCAG AA for body text); on black it is 1.89:1 (fails). For text placed on #303E40, use white for the best readability.

What is the closest Tailwind color to #303E40?

The nearest Tailwind CSS token is neutral-700 (#404040).

What colors go well with #303E40?

As a neutral, #303E40 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 #303E40 the same as CSS darkslategray?

No — #303E40 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.

#303E40 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #303E40

Not just a swatch — here's how #303E40 works with other colors. Named schemes with #303E40 in its natural role, and a note on why the supporting colors balance it.

Tech Product Signal · 5 colors

Signal #303E40 Surface #14161A Highlight #F4F6F8 Secondary #596671 Accent #515E60

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 #303E40 Secondary #715117 Surface #E3DCC0 Accent #395143 Anchor #56233F

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.

Japanese Sand Base · 5 colors

Base #303E40 Surface #EDEADC Highlight #F4F2E7 Secondary #B4B19F Ink #2A2723

Onyx sets a calm, sun-bleached base here, wrapped in bone and paper off-whites and a soft greige, with a single ink accent for wabi-sabi restraint.

Coastal Morning Lead · 5 colors

Lead #303E40 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.

Minimal Editorial Surface · 5 colors

Surface #F6F4EF Accent #303E40 Secondary #5D6263 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 #303E40 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 45/100

Neutral

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

Softness 38/100

Low

Middle-weight — neither delicate nor heavy.

Depth 61/100

High

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

Naturalness 2/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 27/100

Low

A faint retro warmth without tipping into sepia.

Luxury 63/100

High

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

Brand distinctiveness 7/100

Very low

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

UI accent fit 32/100

Low

Workable accent with care around contrast.

Surface fit 56/100

Moderate

Usable as a tinted surface in measured doses.

Print safety 95/100

Very high

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #303E40

For UI

For branding

For interior

For fashion

People also use #303E40 with

Feldgrau Gunmetal Gray Onyx Platinum Outer Space

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 11.1:1. Use

Subtle surface Use #D3DADB for cards and hover fills. Tint 80

Avoid beside #303940 — 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 #303E40 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: #303E40;
  --color-base-rgb: 48 62 64;
  --color-base-oklch: oklch(35.2% 0.019 207.0);
  --color-50: #F6F8F9;
  --color-100: #E8EDEE;
  --color-200: #D1DADC;
  --color-300: #AFBEC1;
  --color-400: #8DA1A5;
  --color-500: #6E8387;
  --color-600: #58676A;
  --color-700: #424C4D;
  --color-800: #2D3334;
  --color-900: #1D2020;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  onyx: {
    50: '#F6F8F9',
    100: '#E8EDEE',
    200: '#D1DADC',
    300: '#AFBEC1',
    400: '#8DA1A5',
    500: '#6E8387',
    600: '#58676A',
    700: '#424C4D',
    800: '#2D3334',
    900: '#1D2020',
  },
}

$base: #303E40;
$base-ink: #FFFFFF;
$base-50: #F6F8F9;
$base-100: #E8EDEE;
$base-200: #D1DADC;
$base-300: #AFBEC1;
$base-400: #8DA1A5;
$base-500: #6E8387;
$base-600: #58676A;
$base-700: #424C4D;
$base-800: #2D3334;
$base-900: #1D2020;
$base-hover: #273133;
$base-subtle: #BDC8CA;

{
    "color": {
        "base": {
            "value": "#303E40",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F6F8F9",
                "type": "color"
            },
            "100": {
                "value": "#E8EDEE",
                "type": "color"
            },
            "200": {
                "value": "#D1DADC",
                "type": "color"
            },
            "300": {
                "value": "#AFBEC1",
                "type": "color"
            },
            "400": {
                "value": "#8DA1A5",
                "type": "color"
            },
            "500": {
                "value": "#6E8387",
                "type": "color"
            },
            "600": {
                "value": "#58676A",
                "type": "color"
            },
            "700": {
                "value": "#424C4D",
                "type": "color"
            },
            "800": {
                "value": "#2D3334",
                "type": "color"
            },
            "900": {
                "value": "#1D2020",
                "type": "color"
            }
        }
    }
}