What color is #2840B8?

#2840B8 is a medium blue. In RGB it is rgb(40, 64, 184), and in HSL hsl(230, 64%, 44%).

Is #2840B8 accessible as text?

On white, #2840B8 has a contrast ratio of 8.35:1 (passes WCAG AA for body text); on black it is 2.52:1 (fails). For text placed on #2840B8, use white for the best readability.

What is the closest Tailwind color to #2840B8?

The nearest Tailwind CSS token is blue-800 (#193CB8).

What colors go well with #2840B8?

#2840B8 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #B8A028. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #2840B8 below.

Is #2840B8 good for buttons?

#2840B8 works well for buttons and highlights, but use white text on #2840B8 — black text only reaches 2.52:1, below the 4.5:1 needed for normal-size labels.

Is #2840B8 the same as CSS darkslateblue?

No — #2840B8 is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#2840B8 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #2840B8

Not just a swatch — here's how #2840B8 works with other colors. Named schemes with #2840B8 in its natural role, and a note on why the supporting colors balance it.

Tech Product Signal · 5 colors

Signal #2840B8 Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #4A69D6

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.

Coastal Morning Lead · 5 colors

Lead #2840B8 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.

Berry & Cream Lead · 5 colors

Lead #2840B8 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 #2840B8 Secondary #6878A1 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.

Sunset Warmth Glow · 5 colors

Glow #2840B8 Secondary #E86A74 Accent #F69250 Anchor #573B58 Surface #F7E7D7

Cobalt Blue 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 #2840B8 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 11/100

Cool

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

Softness 29/100

Low

Firm and assertive — carries weight and contrast.

Depth 60/100

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 24/100

Low

Clean and current — no dusty, aged cast.

Luxury 57/100

Moderate

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

Brand distinctiveness 73/100

High

Bold and ownable — memorable as a primary brand color.

UI accent fit 78/100

High

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

Surface fit 12/100

Very low

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

Print safety 67/100

High

Prints close, with a slight loss of vibrancy.

Pairs with #2840B8

For UI

For branding

For interior

For fashion

People also use #2840B8 with

Carolina Blue Grape Brass 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 8.3:1. Use

Subtle surface Use #D5DAF0 for cards and hover fills. Tint 80

Avoid beside #4028B8 — 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 #2840B8 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: #2840B8;
  --color-base-rgb: 40 64 184;
  --color-base-oklch: oklch(43.7% 0.190 268.2);
  --color-50: #F2F4FD;
  --color-100: #DDE1F8;
  --color-200: #BCC5F0;
  --color-300: #8E9CE1;
  --color-400: #6476CE;
  --color-500: #4255B3;
  --color-600: #394689;
  --color-700: #2E3661;
  --color-800: #212640;
  --color-900: #161927;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cobalt-blue: {
    50: '#F2F4FD',
    100: '#DDE1F8',
    200: '#BCC5F0',
    300: '#8E9CE1',
    400: '#6476CE',
    500: '#4255B3',
    600: '#394689',
    700: '#2E3661',
    800: '#212640',
    900: '#161927',
  },
}

$base: #2840B8;
$base-ink: #FFFFFF;
$base-50: #F2F4FD;
$base-100: #DDE1F8;
$base-200: #BCC5F0;
$base-300: #8E9CE1;
$base-400: #6476CE;
$base-500: #4255B3;
$base-600: #394689;
$base-700: #2E3661;
$base-800: #212640;
$base-900: #161927;
$base-hover: #203393;
$base-subtle: #BFC6E9;

{
    "color": {
        "base": {
            "value": "#2840B8",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F2F4FD",
                "type": "color"
            },
            "100": {
                "value": "#DDE1F8",
                "type": "color"
            },
            "200": {
                "value": "#BCC5F0",
                "type": "color"
            },
            "300": {
                "value": "#8E9CE1",
                "type": "color"
            },
            "400": {
                "value": "#6476CE",
                "type": "color"
            },
            "500": {
                "value": "#4255B3",
                "type": "color"
            },
            "600": {
                "value": "#394689",
                "type": "color"
            },
            "700": {
                "value": "#2E3661",
                "type": "color"
            },
            "800": {
                "value": "#212640",
                "type": "color"
            },
            "900": {
                "value": "#161927",
                "type": "color"
            }
        }
    }
}

Palettes built on #2840B8

Color Lab

Pairs with #2840B8

UI roles & guardrails

In real applications

Scales

Every model

Export