What color is #3F00FF?

Ultramarine (#3F00FF) is a medium, vivid indigo. In RGB it is rgb(63, 0, 255), and in HSL hsl(255, 100%, 50%).

Is #3F00FF accessible as text?

On white, #3F00FF has a contrast ratio of 7.91:1 (passes WCAG AA for body text); on black it is 2.66:1 (fails). For text placed on #3F00FF, use white for the best readability.

What is the closest Tailwind color to #3F00FF?

The nearest Tailwind CSS token is indigo-600 (#4F39F6).

What colors go well with #3F00FF?

#3F00FF pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #BFFF00. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #3F00FF below.

Is Ultramarine good for buttons?

Ultramarine works well for buttons and highlights, but use white text on #3F00FF — black text only reaches 2.66:1, below the 4.5:1 needed for normal-size labels.

Is Ultramarine a CSS named color?

No — Ultramarine is not a standard CSS named color; use the hex value #3F00FF in CSS. The closest CSS named color is blue.

Ultramarine (#3F00FF) Color Palette, HEX, RGB & Design Ideas

Palettes built on Ultramarine

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

Tech Product Signal · 5 colors

Signal #3F00FF Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #565AFF

Ultramarine is the vivid signal in this product UI — on a near-black surface with cool white, a slate grey and a lighter tint of Ultramarine.

Coastal Morning Lead · 5 colors

Lead #3F00FF Accent #A5C4C2 Surface #EAD5C0 Secondary #9AA0A1 Anchor #21344A

Ultramarine 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 #3F00FF Surface #F6E5D8 Anchor #5B2143 Accent #E5C2C9 Secondary #322B2F

Ultramarine 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 #3F00FF Secondary #707FC3 Support #9D8F88 Ink #18140F

Ultramarine 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 Ultramarine carrying the quiet middle.

Sunset Warmth Glow · 5 colors

Glow #3F00FF Secondary #E86A72 Accent #F6924F Anchor #573B58 Surface #F7E7D7

Ultramarine 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 Ultramarine 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 20/100

Very low

Firm and assertive — carries weight and contrast.

Depth 60/100

High

Mid depth — usable as an accent or a muted ground.

Naturalness 0/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 0/100

Very low

Clean and current — no dusty, aged cast.

Luxury 46/100

Moderate

Understated — leans refined without going austere.

Brand distinctiveness 100/100

Very high

Bold and ownable — memorable as a primary brand color.

UI accent fit 33/100

Low

Workable accent with care around contrast.

Surface fit 9/100

Very low

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

Print safety 51/100

Moderate

Prints close, with a slight loss of vibrancy.

Pairs with Ultramarine

For UI

For branding

For interior

For fashion

People also use Ultramarine with

Azure Electric Purple Yellow Green Gainsboro Russian Violet

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 7.9:1. Use

Subtle surface Use #DCD3F8 for cards and hover fills. Tint 80

Avoid beside #9500FF — 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 Ultramarine 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: #3F00FF;
  --color-base-rgb: 63 0 255;
  --color-base-oklch: oklch(47.3% 0.301 273.6);
  --color-50: #F4F0FE;
  --color-100: #E1D8FD;
  --color-200: #C3B1FC;
  --color-300: #9777F8;
  --color-400: #7046EC;
  --color-500: #4E22D2;
  --color-600: #42239F;
  --color-700: #331F70;
  --color-800: #241848;
  --color-900: #18112C;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  ultramarine: {
    50: '#F4F0FE',
    100: '#E1D8FD',
    200: '#C3B1FC',
    300: '#9777F8',
    400: '#7046EC',
    500: '#4E22D2',
    600: '#42239F',
    700: '#331F70',
    800: '#241848',
    900: '#18112C',
  },
}

$base: #3F00FF;
$base-ink: #FFFFFF;
$base-50: #F4F0FE;
$base-100: #E1D8FD;
$base-200: #C3B1FC;
$base-300: #9777F8;
$base-400: #7046EC;
$base-500: #4E22D2;
$base-600: #42239F;
$base-700: #331F70;
$base-800: #241848;
$base-900: #18112C;
$base-hover: #3300CC;
$base-subtle: #CABCF6;

{
    "color": {
        "base": {
            "value": "#3F00FF",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F4F0FE",
                "type": "color"
            },
            "100": {
                "value": "#E1D8FD",
                "type": "color"
            },
            "200": {
                "value": "#C3B1FC",
                "type": "color"
            },
            "300": {
                "value": "#9777F8",
                "type": "color"
            },
            "400": {
                "value": "#7046EC",
                "type": "color"
            },
            "500": {
                "value": "#4E22D2",
                "type": "color"
            },
            "600": {
                "value": "#42239F",
                "type": "color"
            },
            "700": {
                "value": "#331F70",
                "type": "color"
            },
            "800": {
                "value": "#241848",
                "type": "color"
            },
            "900": {
                "value": "#18112C",
                "type": "color"
            }
        }
    }
}

Palettes built on Ultramarine

Color Lab

Pairs with Ultramarine

UI roles & guardrails

In real applications

Scales

Every model

Export