What color is #243FDB?

#243FDB is a medium, vivid blue. In RGB it is rgb(36, 63, 219), and in HSL hsl(231, 72%, 50%).

Is #243FDB accessible as text?

On white, #243FDB has a contrast ratio of 7.48:1 (passes WCAG AA for body text); on black it is 2.81:1 (fails). For text placed on #243FDB, use white for the best readability.

What is the closest Tailwind color to #243FDB?

The nearest Tailwind CSS token is blue-700 (#1447E6).

What colors go well with #243FDB?

#243FDB pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #DBC024. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #243FDB below.

Is #243FDB good for buttons?

#243FDB works well for buttons and highlights, but use white text on #243FDB — black text only reaches 2.81:1, below the 4.5:1 needed for normal-size labels.

Is #243FDB the same as CSS blue?

No — #243FDB is not the CSS named color blue, but blue (#0000FF) is the closest CSS named color.

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

Palettes built on #243FDB

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

Tech Product Signal · 5 colors

Signal #243FDB Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #456EF8

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

Coastal Morning Lead · 5 colors

Lead #243FDB Accent #A5C4C2 Surface #EAD5C0 Secondary #9AA0A1 Anchor #21344A

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

Berry & Cream Lead · 5 colors

Lead #243FDB Surface #F6E5D8 Anchor #5B2143 Accent #E5C2CA Secondary #322B2F

Cerulean 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 #243FDB Secondary #6D81B5 Support #9D8F88 Ink #18140F

Cerulean 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 Cerulean carrying the quiet middle.

Sunset Warmth Glow · 5 colors

Glow #243FDB Secondary #E86A74 Accent #F79250 Anchor #573B58 Surface #F7E7D7

Cerulean glows at the center of this sunset palette, joined by coral and gold, deepened by a plum anchor and cooled with cream.

Build a working theme in the generator →

Color Lab

How #243FDB 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 10/100

Cool

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

Softness 26/100

Low

Firm and assertive — carries weight and contrast.

Depth 58/100

Moderate

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

Naturalness 0/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 12/100

Very low

Clean and current — no dusty, aged cast.

Luxury 51/100

Moderate

Understated — leans refined without going austere.

Brand distinctiveness 91/100

Very high

Bold and ownable — memorable as a primary brand color.

UI accent fit 65/100

High

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

Surface fit 10/100

Very low

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

Print safety 58/100

Moderate

Prints close, with a slight loss of vibrancy.

Pairs with #243FDB

For UI

For branding

For interior

For fashion

People also use #243FDB with

Picton Blue Blue Violet Mustard Yellow Gainsboro Prussian Blue

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 7.5:1. Use

Subtle surface Use #D8DCF3 for cards and hover fills. Tint 80

Avoid beside #4524DB — 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 #243FDB 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: #243FDB;
  --color-base-rgb: 36 63 219;
  --color-base-oklch: oklch(46.8% 0.235 267.2);
  --color-50: #F1F3FD;
  --color-100: #DBE0FA;
  --color-200: #B9C2F3;
  --color-300: #8997E6;
  --color-400: #5D6FD5;
  --color-500: #3B4EBA;
  --color-600: #34428E;
  --color-700: #2A3364;
  --color-800: #1F2442;
  --color-900: #151828;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cerulean: {
    50: '#F1F3FD',
    100: '#DBE0FA',
    200: '#B9C2F3',
    300: '#8997E6',
    400: '#5D6FD5',
    500: '#3B4EBA',
    600: '#34428E',
    700: '#2A3364',
    800: '#1F2442',
    900: '#151828',
  },
}

$base: #243FDB;
$base-ink: #FFFFFF;
$base-50: #F1F3FD;
$base-100: #DBE0FA;
$base-200: #B9C2F3;
$base-300: #8997E6;
$base-400: #5D6FD5;
$base-500: #3B4EBA;
$base-600: #34428E;
$base-700: #2A3364;
$base-800: #1F2442;
$base-900: #151828;
$base-hover: #1D33AF;
$base-subtle: #C4CAEE;

{
    "color": {
        "base": {
            "value": "#243FDB",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F1F3FD",
                "type": "color"
            },
            "100": {
                "value": "#DBE0FA",
                "type": "color"
            },
            "200": {
                "value": "#B9C2F3",
                "type": "color"
            },
            "300": {
                "value": "#8997E6",
                "type": "color"
            },
            "400": {
                "value": "#5D6FD5",
                "type": "color"
            },
            "500": {
                "value": "#3B4EBA",
                "type": "color"
            },
            "600": {
                "value": "#34428E",
                "type": "color"
            },
            "700": {
                "value": "#2A3364",
                "type": "color"
            },
            "800": {
                "value": "#1F2442",
                "type": "color"
            },
            "900": {
                "value": "#151828",
                "type": "color"
            }
        }
    }
}

Palettes built on #243FDB

Color Lab

Pairs with #243FDB

UI roles & guardrails

In real applications

Scales

Every model

Export