What color is #233E9F?

#233E9F is a dark blue. In RGB it is rgb(35, 62, 159), and in HSL hsl(227, 64%, 38%).

Is #233E9F accessible as text?

On white, #233E9F has a contrast ratio of 9.29:1 (passes WCAG AA for body text); on black it is 2.26:1 (fails). For text placed on #233E9F, use white for the best readability.

What is the closest Tailwind color to #233E9F?

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

What colors go well with #233E9F?

#233E9F pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #9F8423. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #233E9F below.

Is #233E9F good for buttons?

#233E9F works well for buttons and highlights, but use white text on #233E9F — black text only reaches 2.26:1, below the 4.5:1 needed for normal-size labels.

Is #233E9F the same as CSS darkslateblue?

No — #233E9F is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#233E9F Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #233E9F

Not just a swatch — here's how #233E9F works with other colors. Named schemes with #233E9F in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #233E9F Accent #A5C4C2 Surface #EAD5C0 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 #233E9F Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #4565BE

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 #233E9F Secondary #7F4535 Surface #EED7C2 Accent #365246 Anchor #58223A

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 #233E9F Surface #F6E5D8 Anchor #5B2143 Accent #E5C2CA 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 #233E9F Secondary #627092 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 #233E9F 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 12/100

Cool

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

Softness 30/100

Low

Firm and assertive — carries weight and contrast.

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 31/100

Low

A faint retro warmth without tipping into sepia.

Luxury 62/100

High

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

Brand distinctiveness 43/100

Moderate

Recognisable but shares space with nearby hues.

UI accent fit 76/100

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 71/100

High

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #233E9F

For UI

For branding

For interior

For fashion

People also use #233E9F with

Bondi Blue Rebecca Purple Dark Goldenrod Gainsboro Gunmetal 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 9.3:1. Use

Subtle surface Use #D1D7EE for cards and hover fills. Tint 80

Avoid beside #31239F — 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 #233E9F at work across the surfaces designers actually ship.

Website / UI

Northwind Sign up

Build faster.

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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: #233E9F;
  --color-base-rgb: 35 62 159;
  --color-base-oklch: oklch(40.8% 0.161 266.9);
  --color-50: #F2F4FD;
  --color-100: #DDE3F8;
  --color-200: #BCC7F0;
  --color-300: #8EA0E1;
  --color-400: #647BCE;
  --color-500: #425AB3;
  --color-600: #394A89;
  --color-700: #2E3961;
  --color-800: #212840;
  --color-900: #161A27;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cobalt-blue: {
    50: '#F2F4FD',
    100: '#DDE3F8',
    200: '#BCC7F0',
    300: '#8EA0E1',
    400: '#647BCE',
    500: '#425AB3',
    600: '#394A89',
    700: '#2E3961',
    800: '#212840',
    900: '#161A27',
  },
}

$base: #233E9F;
$base-ink: #FFFFFF;
$base-50: #F2F4FD;
$base-100: #DDE3F8;
$base-200: #BCC7F0;
$base-300: #8EA0E1;
$base-400: #647BCE;
$base-500: #425AB3;
$base-600: #394A89;
$base-700: #2E3961;
$base-800: #212840;
$base-900: #161A27;
$base-hover: #1C317F;
$base-subtle: #B9C2E7;

{
    "color": {
        "base": {
            "value": "#233E9F",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F2F4FD",
                "type": "color"
            },
            "100": {
                "value": "#DDE3F8",
                "type": "color"
            },
            "200": {
                "value": "#BCC7F0",
                "type": "color"
            },
            "300": {
                "value": "#8EA0E1",
                "type": "color"
            },
            "400": {
                "value": "#647BCE",
                "type": "color"
            },
            "500": {
                "value": "#425AB3",
                "type": "color"
            },
            "600": {
                "value": "#394A89",
                "type": "color"
            },
            "700": {
                "value": "#2E3961",
                "type": "color"
            },
            "800": {
                "value": "#212840",
                "type": "color"
            },
            "900": {
                "value": "#161A27",
                "type": "color"
            }
        }
    }
}

Palettes built on #233E9F

Color Lab

Pairs with #233E9F

UI roles & guardrails

In real applications

Scales

Every model

Export