What color is #100A8A?

#100A8A is a dark, vivid blue. In RGB it is rgb(16, 10, 138), and in HSL hsl(243, 86%, 29%).

Is #100A8A accessible as text?

On white, #100A8A has a contrast ratio of 14.66:1 (passes WCAG AA for body text); on black it is 1.43:1 (fails). For text placed on #100A8A, use white for the best readability.

What is the closest Tailwind color to #100A8A?

The nearest Tailwind CSS token is indigo-900 (#312C85).

What colors go well with #100A8A?

#100A8A pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #838A0A. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #100A8A below.

Is #100A8A good for buttons?

#100A8A works well for buttons and highlights, but use white text on #100A8A — black text only reaches 1.43:1, below the 4.5:1 needed for normal-size labels.

Is #100A8A the same as CSS darkblue?

No — #100A8A is not the CSS named color darkblue, but darkblue (#00008B) is the closest CSS named color.

#100A8A Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #100A8A

Not just a swatch — here's how #100A8A works with other colors. Named schemes with #100A8A in its natural role, and a note on why the supporting colors balance it.

Luxury Packaging Feature · 5 colors

Feature #100A8A Anchor #141210 Accent #DC9659 Secondary #252933 Surface #F4ECE3

Phthalo Blue carries the depth in this luxury scheme, offset by a brass accent and near-black and held together by a deep neutral and an off-white surface.

Tech Product Signal · 5 colors

Signal #100A8A Surface #14161A Highlight #F4F6F8 Secondary #5B6672 Accent #273FA8

Phthalo 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 Phthalo Blue.

Moody Editorial Color · 5 colors

Color #100A8A Anchor #2A2A2E Secondary #6E6E74 Surface #EEE5DB Accent #150047

Phthalo Blue adds the colour to this moody editorial scheme — charcoal and a mid-grey around it, a bone highlight, and a muted jewel accent drawn from Phthalo Blue.

Coastal Morning Lead · 5 colors

Lead #100A8A Accent #A5C4C2 Surface #EAD5C0 Secondary #9AA0A1 Anchor #21344A

Phthalo Blue opens this coastal palette with sea-glass and warm sand alongside it, grounded by driftwood grey and a deep-navy anchor.

Minimal Editorial Surface · 5 colors

Surface #F8F4EF Accent #100A8A Secondary #435177 Support #9D8F88 Ink #18140F

Phthalo 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 Phthalo Blue carrying the quiet middle.

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Color Lab

How #100A8A 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 21/100

Low

Firm and assertive — carries weight and contrast.

Depth 74/100

High

Deep and grounding — anchors a layout, strong dark-mode base.

Naturalness 0/100

Very low

Reads engineered rather than organic — synthetic, digital.

Vintage feel 18/100

Very low

Clean and current — no dusty, aged cast.

Luxury 68/100

High

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 36/100

Low

Workable accent with care around contrast.

Surface fit 21/100

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 #100A8A

For UI

For branding

For interior

For fashion

People also use #100A8A with

Denim Blue Indigo Olive 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 14.7:1. Use

Subtle surface Use #C7C4F1 for cards and hover fills. Tint 80

Avoid beside #3B0A8A — 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 #100A8A 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: #100A8A;
  --color-base-rgb: 16 10 138;
  --color-base-oklch: oklch(30.0% 0.189 268.1);
  --color-50: #F1F0FE;
  --color-100: #DAD8FD;
  --color-200: #B7B3F9;
  --color-300: #8680EF;
  --color-400: #5952E0;
  --color-500: #362FC6;
  --color-600: #312B96;
  --color-700: #28256A;
  --color-800: #1E1C45;
  --color-900: #14132A;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  phthalo-blue: {
    50: '#F1F0FE',
    100: '#DAD8FD',
    200: '#B7B3F9',
    300: '#8680EF',
    400: '#5952E0',
    500: '#362FC6',
    600: '#312B96',
    700: '#28256A',
    800: '#1E1C45',
    900: '#14132A',
  },
}

$base: #100A8A;
$base-ink: #FFFFFF;
$base-50: #F1F0FE;
$base-100: #DAD8FD;
$base-200: #B7B3F9;
$base-300: #8680EF;
$base-400: #5952E0;
$base-500: #362FC6;
$base-600: #312B96;
$base-700: #28256A;
$base-800: #1E1C45;
$base-900: #14132A;
$base-hover: #0D086E;
$base-subtle: #A9A5EC;

{
    "color": {
        "base": {
            "value": "#100A8A",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F1F0FE",
                "type": "color"
            },
            "100": {
                "value": "#DAD8FD",
                "type": "color"
            },
            "200": {
                "value": "#B7B3F9",
                "type": "color"
            },
            "300": {
                "value": "#8680EF",
                "type": "color"
            },
            "400": {
                "value": "#5952E0",
                "type": "color"
            },
            "500": {
                "value": "#362FC6",
                "type": "color"
            },
            "600": {
                "value": "#312B96",
                "type": "color"
            },
            "700": {
                "value": "#28256A",
                "type": "color"
            },
            "800": {
                "value": "#1E1C45",
                "type": "color"
            },
            "900": {
                "value": "#14132A",
                "type": "color"
            }
        }
    }
}

Palettes built on #100A8A

Color Lab

Pairs with #100A8A

UI roles & guardrails

In real applications

Scales

Every model

Export