What color is #21499E?

#21499E is a dark blue. In RGB it is rgb(33, 73, 158), and in HSL hsl(221, 65%, 37%).

Is #21499E accessible as text?

On white, #21499E has a contrast ratio of 8.36:1 (passes WCAG AA for body text); on black it is 2.51:1 (fails). For text placed on #21499E, use white for the best readability.

What is the closest Tailwind color to #21499E?

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

What colors go well with #21499E?

#21499E pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #9C7521. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #21499E below.

Is #21499E good for buttons?

#21499E works well for buttons and highlights, but use white text on #21499E — black text only reaches 2.51:1, below the 4.5:1 needed for normal-size labels.

Is #21499E the same as CSS darkslateblue?

No — #21499E is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#21499E Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #21499E

Not just a swatch — here's how #21499E works with other colors. Named schemes with #21499E in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #21499E Accent #A5C4C1 Surface #DDDBBF 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 #21499E Surface #14161A Highlight #F4F6F8 Secondary #5A6672 Accent #476EBD

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 #21499E Secondary #7F4536 Surface #E1DDC1 Accent #375246 Anchor #57223A

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 #21499E Surface #F6E5D8 Anchor #5A2144 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 #F8F4EF Accent #21499E Secondary #677796 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 #21499E 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 33/100

Low

Middle-weight — neither delicate nor heavy.

Depth 59/100

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 36/100

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 39/100

Low

Recognisable but shares space with nearby hues.

UI accent fit 84/100

Very 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 73/100

High

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #21499E

For UI

For branding

For interior

For fashion

People also use #21499E with

Verdigris Indigo Olive Brown 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 8.4:1. Use

Subtle surface Use #D0D9EE for cards and hover fills. Tint 80

Avoid beside #23219C — 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 #21499E at work across the surfaces designers actually ship.

Website / UI

Northwind Sign up

Build faster.

A working theme, generated in seconds.

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: #21499E;
  --color-base-rgb: 33 73 158;
  --color-base-oklch: oklch(42.9% 0.146 262.8);
  --color-50: #F2F5FD;
  --color-100: #DDE5F9;
  --color-200: #BCCDF1;
  --color-300: #8EA8E2;
  --color-400: #6385CF;
  --color-500: #4165B4;
  --color-600: #385289;
  --color-700: #2D3E62;
  --color-800: #212B40;
  --color-900: #161B27;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cobalt-blue: {
    50: '#F2F5FD',
    100: '#DDE5F9',
    200: '#BCCDF1',
    300: '#8EA8E2',
    400: '#6385CF',
    500: '#4165B4',
    600: '#385289',
    700: '#2D3E62',
    800: '#212B40',
    900: '#161B27',
  },
}

$base: #21499E;
$base-ink: #FFFFFF;
$base-50: #F2F5FD;
$base-100: #DDE5F9;
$base-200: #BCCDF1;
$base-300: #8EA8E2;
$base-400: #6385CF;
$base-500: #4165B4;
$base-600: #385289;
$base-700: #2D3E62;
$base-800: #212B40;
$base-900: #161B27;
$base-hover: #1A397D;
$base-subtle: #B7C6E7;

{
    "color": {
        "base": {
            "value": "#21499E",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F2F5FD",
                "type": "color"
            },
            "100": {
                "value": "#DDE5F9",
                "type": "color"
            },
            "200": {
                "value": "#BCCDF1",
                "type": "color"
            },
            "300": {
                "value": "#8EA8E2",
                "type": "color"
            },
            "400": {
                "value": "#6385CF",
                "type": "color"
            },
            "500": {
                "value": "#4165B4",
                "type": "color"
            },
            "600": {
                "value": "#385289",
                "type": "color"
            },
            "700": {
                "value": "#2D3E62",
                "type": "color"
            },
            "800": {
                "value": "#212B40",
                "type": "color"
            },
            "900": {
                "value": "#161B27",
                "type": "color"
            }
        }
    }
}