What color is #3F50BB?

#3F50BB is a medium blue. In RGB it is rgb(63, 80, 187), and in HSL hsl(232, 50%, 49%).

Is #3F50BB accessible as text?

On white, #3F50BB has a contrast ratio of 6.83:1 (passes WCAG AA for body text); on black it is 3.08:1 (fails). For text placed on #3F50BB, use white for the best readability.

What is the closest Tailwind color to #3F50BB?

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

What colors go well with #3F50BB?

#3F50BB pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #BBAB3E. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #3F50BB below.

Is #3F50BB good for buttons?

#3F50BB works well for buttons and highlights, but use white text on #3F50BB — black text only reaches 3.08:1, below the 4.5:1 needed for normal-size labels.

Is #3F50BB the same as CSS slateblue?

No — #3F50BB is not the CSS named color slateblue, but slateblue (#6A5ACD) is the closest CSS named color.

#3F50BB Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #3F50BB

Not just a swatch — here's how #3F50BB works with other colors. Named schemes with #3F50BB in its natural role, and a note on why the supporting colors balance it.

Coastal Morning Lead · 5 colors

Lead #3F50BB 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 #3F50BB Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #6177DA

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 #3F50BB Secondary #7F4535 Surface #EED7C2 Accent #365247 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 #3F50BB 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 #3F50BB Secondary #7A85AB 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 #3F50BB 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 34/100

Low

Middle-weight — neither delicate nor heavy.

Depth 54/100

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 33/100

Low

A faint retro warmth without tipping into sepia.

Luxury 55/100

Moderate

Understated — leans refined without going austere.

Brand distinctiveness 46/100

Moderate

Recognisable but shares space with nearby hues.

UI accent fit 93/100

Very high

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

Surface fit 9/100

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 #3F50BB

For UI

For branding

For interior

For fashion

People also use #3F50BB with

Iceberg Grape Brass Gainsboro Prussian Blue

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 6.8:1. Use

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

Avoid beside #573EBB — 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 #3F50BB at work across the surfaces designers actually ship.

Website / UI

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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: #3F50BB;
  --color-base-rgb: 63 80 187;
  --color-base-oklch: oklch(48.1% 0.168 271.7);
  --color-50: #F3F4FC;
  --color-100: #E0E3F5;
  --color-200: #C2C7EB;
  --color-300: #97A0D8;
  --color-400: #707BC2;
  --color-500: #4E5AA6;
  --color-600: #424A80;
  --color-700: #33395C;
  --color-800: #24283C;
  --color-900: #181A25;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  cerulean: {
    50: '#F3F4FC',
    100: '#E0E3F5',
    200: '#C2C7EB',
    300: '#97A0D8',
    400: '#707BC2',
    500: '#4E5AA6',
    600: '#424A80',
    700: '#33395C',
    800: '#24283C',
    900: '#181A25',
  },
}

$base: #3F50BB;
$base-ink: #FFFFFF;
$base-50: #F3F4FC;
$base-100: #E0E3F5;
$base-200: #C2C7EB;
$base-300: #97A0D8;
$base-400: #707BC2;
$base-500: #4E5AA6;
$base-600: #424A80;
$base-700: #33395C;
$base-800: #24283C;
$base-900: #181A25;
$base-hover: #323F96;
$base-subtle: #C9CDE7;

{
    "color": {
        "base": {
            "value": "#3F50BB",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F3F4FC",
                "type": "color"
            },
            "100": {
                "value": "#E0E3F5",
                "type": "color"
            },
            "200": {
                "value": "#C2C7EB",
                "type": "color"
            },
            "300": {
                "value": "#97A0D8",
                "type": "color"
            },
            "400": {
                "value": "#707BC2",
                "type": "color"
            },
            "500": {
                "value": "#4E5AA6",
                "type": "color"
            },
            "600": {
                "value": "#424A80",
                "type": "color"
            },
            "700": {
                "value": "#33395C",
                "type": "color"
            },
            "800": {
                "value": "#24283C",
                "type": "color"
            },
            "900": {
                "value": "#181A25",
                "type": "color"
            }
        }
    }
}

Palettes built on #3F50BB

Color Lab

Pairs with #3F50BB

UI roles & guardrails

In real applications

Scales

Every model

Export