What color is #15519B?

#15519B is a dark, vivid blue. In RGB it is rgb(21, 81, 155), and in HSL hsl(213, 76%, 35%).

Is #15519B accessible as text?

On white, #15519B has a contrast ratio of 7.83:1 (passes WCAG AA for body text); on black it is 2.68:1 (fails). For text placed on #15519B, use white for the best readability.

What is the closest Tailwind color to #15519B?

The nearest Tailwind CSS token is sky-800 (#00598A).

What colors go well with #15519B?

#15519B pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #9D6015. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #15519B below.

Is #15519B good for buttons?

#15519B works well for buttons and highlights, but use white text on #15519B — black text only reaches 2.68:1, below the 4.5:1 needed for normal-size labels.

Is #15519B the same as CSS darkslateblue?

No — #15519B is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#15519B Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #15519B

Not just a swatch — here's how #15519B works with other colors. Named schemes with #15519B in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #15519B Accent #A5C4C1 Surface #DDDBBF Secondary #9AA0A1 Anchor #20344A

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 #15519B Surface #14161A Highlight #F4F6F8 Secondary #5A6672 Accent #4275BB

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 #15519B Secondary #7F4537 Surface #E1DDC1 Accent #375246 Anchor #57233B

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 #15519B Surface #EDE9D6 Anchor #5A2145 Accent #E4C2CA 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 #F6F4EF Accent #15519B Secondary #697C97 Support #9D8F89 Ink #16140F

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 #15519B 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 14/100

Cool

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

Softness 35/100

Low

Middle-weight — neither delicate nor heavy.

Depth 57/100

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 39/100

Low

A faint retro warmth without tipping into sepia.

Luxury 61/100

High

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

Brand distinctiveness 36/100

Low

Recognisable but shares space with nearby hues.

UI accent fit 87/100

Very high

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

Surface fit 15/100

Very low

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

Print safety 73/100

High

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #15519B

For UI

For branding

For interior

For fashion

People also use #15519B with

Tiffany Blue Zaffre Sienna 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 7.8:1. Use

Subtle surface Use #CCDCF0 for cards and hover fills. Tint 80

Avoid beside #15259D — 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 #15519B at work across the surfaces designers actually ship.

Website / UI

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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: #15519B;
  --color-base-rgb: 21 81 155;
  --color-base-oklch: oklch(44.1% 0.135 256.4);
  --color-50: #F1F7FE;
  --color-100: #DAE9FB;
  --color-200: #B7D3F5;
  --color-300: #87B3E9;
  --color-400: #5A93D8;
  --color-500: #3774BD;
  --color-600: #325C90;
  --color-700: #294466;
  --color-800: #1E2F43;
  --color-900: #141E29;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cobalt-blue: {
    50: '#F1F7FE',
    100: '#DAE9FB',
    200: '#B7D3F5',
    300: '#87B3E9',
    400: '#5A93D8',
    500: '#3774BD',
    600: '#325C90',
    700: '#294466',
    800: '#1E2F43',
    900: '#141E29',
  },
}

$base: #15519B;
$base-ink: #FFFFFF;
$base-50: #F1F7FE;
$base-100: #DAE9FB;
$base-200: #B7D3F5;
$base-300: #87B3E9;
$base-400: #5A93D8;
$base-500: #3774BD;
$base-600: #325C90;
$base-700: #294466;
$base-800: #1E2F43;
$base-900: #141E29;
$base-hover: #11427E;
$base-subtle: #B1CAEA;

{
    "color": {
        "base": {
            "value": "#15519B",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F1F7FE",
                "type": "color"
            },
            "100": {
                "value": "#DAE9FB",
                "type": "color"
            },
            "200": {
                "value": "#B7D3F5",
                "type": "color"
            },
            "300": {
                "value": "#87B3E9",
                "type": "color"
            },
            "400": {
                "value": "#5A93D8",
                "type": "color"
            },
            "500": {
                "value": "#3774BD",
                "type": "color"
            },
            "600": {
                "value": "#325C90",
                "type": "color"
            },
            "700": {
                "value": "#294466",
                "type": "color"
            },
            "800": {
                "value": "#1E2F43",
                "type": "color"
            },
            "900": {
                "value": "#141E29",
                "type": "color"
            }
        }
    }
}