What color is #3F56BB?

#3F56BB is a medium blue. In RGB it is rgb(63, 86, 187), and in HSL hsl(229, 50%, 49%).

Is #3F56BB accessible as text?

On white, #3F56BB has a contrast ratio of 6.44:1 (passes WCAG AA for body text); on black it is 3.26:1 (fails). For text placed on #3F56BB, use white for the best readability.

What is the closest Tailwind color to #3F56BB?

The nearest Tailwind CSS token is sky-700 (#0069A8).

What colors go well with #3F56BB?

#3F56BB pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #BBA53E. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #3F56BB below.

Is #3F56BB good for buttons?

#3F56BB works well for buttons and highlights, but use white text on #3F56BB — black text only reaches 3.26:1, below the 4.5:1 needed for normal-size labels.

Is #3F56BB the same as CSS slateblue?

No — #3F56BB is not the CSS named color slateblue, but slateblue (#6A5ACD) is the closest CSS named color.

#3F56BB Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #3F56BB

Not just a swatch — here's how #3F56BB works with other colors. Named schemes with #3F56BB in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #3F56BB 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.

Tech Product Signal · 5 colors

Signal #3F56BB Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #627DDA

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.

Vintage Leather Lead · 5 colors

Lead #3F56BB Secondary #7F4535 Surface #EED7C2 Accent #365246 Anchor #582239

Cerulean 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 #3F56BB Surface #F6E5D8 Anchor #5B2143 Accent #E5C2C9 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 #3F56BB Secondary #7C89AD 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.

Build a working theme in the generator →

Color Lab

How #3F56BB 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 13/100

Cool

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

Softness 36/100

Low

Middle-weight — neither delicate nor heavy.

Depth 53/100

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 55/100

Moderate

Understated — leans refined without going austere.

Brand distinctiveness 43/100

Moderate

Recognisable but shares space with nearby hues.

UI accent fit 96/100

Very high

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

Surface fit 8/100

Very low

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

Print safety 72/100

High

Reproduces faithfully in CMYK — safe for packaging and print.

Pairs with #3F56BB

For UI

For branding

For interior

For fashion

People also use #3F56BB with

Iceberg Grape Brass Gainsboro Gunmetal Gray

UI roles & guardrails

Primary action Safe as a filled button with white label. AA

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 6.4:1. Use

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

Avoid beside #513EBB — 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 #3F56BB at work across the surfaces designers actually ship.

Website / UI

Northwind Sign up

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: #3F56BB;
  --color-base-rgb: 63 86 187;
  --color-base-oklch: oklch(49.3% 0.161 269.9);
  --color-50: #F3F5FC;
  --color-100: #E0E4F5;
  --color-200: #C2C9EB;
  --color-300: #97A3D8;
  --color-400: #707FC2;
  --color-500: #4E5FA6;
  --color-600: #424D80;
  --color-700: #333B5C;
  --color-800: #24293C;
  --color-900: #181A25;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cerulean: {
    50: '#F3F5FC',
    100: '#E0E4F5',
    200: '#C2C9EB',
    300: '#97A3D8',
    400: '#707FC2',
    500: '#4E5FA6',
    600: '#424D80',
    700: '#333B5C',
    800: '#24293C',
    900: '#181A25',
  },
}

$base: #3F56BB;
$base-ink: #FFFFFF;
$base-50: #F3F5FC;
$base-100: #E0E4F5;
$base-200: #C2C9EB;
$base-300: #97A3D8;
$base-400: #707FC2;
$base-500: #4E5FA6;
$base-600: #424D80;
$base-700: #333B5C;
$base-800: #24293C;
$base-900: #181A25;
$base-hover: #324496;
$base-subtle: #C9CFE7;

{
    "color": {
        "base": {
            "value": "#3F56BB",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F3F5FC",
                "type": "color"
            },
            "100": {
                "value": "#E0E4F5",
                "type": "color"
            },
            "200": {
                "value": "#C2C9EB",
                "type": "color"
            },
            "300": {
                "value": "#97A3D8",
                "type": "color"
            },
            "400": {
                "value": "#707FC2",
                "type": "color"
            },
            "500": {
                "value": "#4E5FA6",
                "type": "color"
            },
            "600": {
                "value": "#424D80",
                "type": "color"
            },
            "700": {
                "value": "#333B5C",
                "type": "color"
            },
            "800": {
                "value": "#24293C",
                "type": "color"
            },
            "900": {
                "value": "#181A25",
                "type": "color"
            }
        }
    }
}

Palettes built on #3F56BB

Color Lab

Pairs with #3F56BB

UI roles & guardrails

In real applications

Scales

Every model

Export