What color is #3F4E8D?

#3F4E8D is a medium blue. In RGB it is rgb(63, 78, 141), and in HSL hsl(228, 38%, 40%).

Is #3F4E8D accessible as text?

On white, #3F4E8D has a contrast ratio of 7.82:1 (passes WCAG AA for body text); on black it is 2.69:1 (fails). For text placed on #3F4E8D, use white for the best readability.

What is the closest Tailwind color to #3F4E8D?

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

What colors go well with #3F4E8D?

#3F4E8D pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #8D7D3F. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #3F4E8D below.

Is #3F4E8D good for buttons?

#3F4E8D works well for buttons and highlights, but use white text on #3F4E8D — black text only reaches 2.69:1, below the 4.5:1 needed for normal-size labels.

Is #3F4E8D the same as CSS darkslateblue?

No — #3F4E8D is not the CSS named color darkslateblue, but darkslateblue (#483D8B) is the closest CSS named color.

#3F4E8D Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #3F4E8D

Not just a swatch — here's how #3F4E8D works with other colors. Named schemes with #3F4E8D in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #3F4E8D Accent #A5C4C2 Surface #EAD5C0 Secondary #9AA0A1 Anchor #21344A

Dark Slate 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 #3F4E8D Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #6172AD

Dark Slate 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 Dark Slate Blue.

Vintage Leather Lead · 5 colors

Lead #3F4E8D Secondary #7F4535 Surface #EED7C2 Accent #365247 Anchor #582239

Dark Slate 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 #3F4E8D Surface #F6E5D8 Anchor #5B2143 Accent #E5C2C9 Secondary #322B2F

Dark Slate 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 #3F4E8D Secondary #737A92 Support #9D8F88 Ink #18140F

Dark Slate 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 Dark Slate Blue carrying the quiet middle.

Build a working theme in the generator →

Color Lab

How #3F4E8D 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 27/100

Cool

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

Softness 38/100

Low

Middle-weight — neither delicate nor heavy.

Depth 56/100

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 50/100

Moderate

A faint retro warmth without tipping into sepia.

Luxury 62/100

High

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

Brand distinctiveness 28/100

Low

Quiet and neutral — a supporting tone, not a signature.

UI accent fit 83/100

Very high

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

Surface fit 24/100

Low

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

Print safety 82/100

Very high

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #3F4E8D

For UI

For branding

For interior

For fashion

People also use #3F4E8D with

Air Force Blue Ultra Violet Olive Brown 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 7.8:1. Use

Subtle surface Use #D8DBE9 for cards and hover fills. Tint 80

Avoid beside #4A3F8D — 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 #3F4E8D 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: #3F4E8D;
  --color-base-rgb: 63 78 141;
  --color-base-oklch: oklch(44.3% 0.105 271.5);
  --color-50: #F4F5FB;
  --color-100: #E2E6F3;
  --color-200: #C7CDE6;
  --color-300: #9FA9D0;
  --color-400: #7A86B8;
  --color-500: #59669C;
  --color-600: #495379;
  --color-700: #383E57;
  --color-800: #272B3A;
  --color-900: #191C24;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  dark-slate-blue: {
    50: '#F4F5FB',
    100: '#E2E6F3',
    200: '#C7CDE6',
    300: '#9FA9D0',
    400: '#7A86B8',
    500: '#59669C',
    600: '#495379',
    700: '#383E57',
    800: '#272B3A',
    900: '#191C24',
  },
}

$base: #3F4E8D;
$base-ink: #FFFFFF;
$base-50: #F4F5FB;
$base-100: #E2E6F3;
$base-200: #C7CDE6;
$base-300: #9FA9D0;
$base-400: #7A86B8;
$base-500: #59669C;
$base-600: #495379;
$base-700: #383E57;
$base-800: #272B3A;
$base-900: #191C24;
$base-hover: #333F71;
$base-subtle: #C4C9DE;

{
    "color": {
        "base": {
            "value": "#3F4E8D",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F4F5FB",
                "type": "color"
            },
            "100": {
                "value": "#E2E6F3",
                "type": "color"
            },
            "200": {
                "value": "#C7CDE6",
                "type": "color"
            },
            "300": {
                "value": "#9FA9D0",
                "type": "color"
            },
            "400": {
                "value": "#7A86B8",
                "type": "color"
            },
            "500": {
                "value": "#59669C",
                "type": "color"
            },
            "600": {
                "value": "#495379",
                "type": "color"
            },
            "700": {
                "value": "#383E57",
                "type": "color"
            },
            "800": {
                "value": "#272B3A",
                "type": "color"
            },
            "900": {
                "value": "#191C24",
                "type": "color"
            }
        }
    }
}