What color is #151B91?

#151B91 is a dark, vivid blue. In RGB it is rgb(21, 27, 145), and in HSL hsl(237, 75%, 33%).

Is #151B91 accessible as text?

On white, #151B91 has a contrast ratio of 13.15:1 (passes WCAG AA for body text); on black it is 1.60:1 (fails). For text placed on #151B91, use white for the best readability.

What is the closest Tailwind color to #151B91?

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

What colors go well with #151B91?

#151B91 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #938D15. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #151B91 below.

Is #151B91 good for buttons?

#151B91 works well for buttons and highlights, but use white text on #151B91 — black text only reaches 1.60:1, below the 4.5:1 needed for normal-size labels.

Is #151B91 the same as CSS darkblue?

No — #151B91 is not the CSS named color darkblue, but darkblue (#00008B) is the closest CSS named color.

#151B91 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #151B91

Not just a swatch — here's how #151B91 works with other colors. Named schemes with #151B91 in its natural role, and a note on why the supporting colors balance it.

Luxury Packaging Feature · 5 colors

Feature #151B91 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.

Moody Editorial Color · 5 colors

Color #151B91 Anchor #2A2A2E Secondary #6E6E74 Surface #EEE5DB Accent #1A004E

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 #151B91 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.

Vintage Leather Lead · 5 colors

Lead #151B91 Secondary #7F4535 Surface #EED7C2 Accent #365246 Anchor #58223A

Phthalo 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.

Minimal Editorial Surface · 5 colors

Surface #F8F4EF Accent #151B91 Secondary #4B597F 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 #151B91 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 23/100

Low

Firm and assertive — carries weight and contrast.

Depth 71/100

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 21/100

Low

Clean and current — no dusty, aged cast.

Luxury 66/100

High

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

Brand distinctiveness 71/100

High

Bold and ownable — memorable as a primary brand color.

UI accent fit 46/100

Moderate

Workable accent with care around contrast.

Surface fit 19/100

Very low

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

Print safety 68/100

High

Prints close, with a slight loss of vibrancy.

Pairs with #151B91

For UI

For branding

For interior

For fashion

People also use #151B91 with

Steel 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 13.1:1. Use

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

Avoid beside #391593 — 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 #151B91 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: #151B91;
  --color-base-rgb: 21 27 145;
  --color-base-oklch: oklch(32.8% 0.185 268.6);
  --color-50: #F1F2FE;
  --color-100: #DADCFB;
  --color-200: #B8BBF5;
  --color-300: #878CE8;
  --color-400: #5B61D7;
  --color-500: #383FBC;
  --color-600: #323790;
  --color-700: #292C66;
  --color-800: #1E2042;
  --color-900: #141529;
  --color-on-base: #FFFFFF;
}

// tailwind.config.js
colors: {
  phthalo-blue: {
    50: '#F1F2FE',
    100: '#DADCFB',
    200: '#B8BBF5',
    300: '#878CE8',
    400: '#5B61D7',
    500: '#383FBC',
    600: '#323790',
    700: '#292C66',
    800: '#1E2042',
    900: '#141529',
  },
}

$base: #151B91;
$base-ink: #FFFFFF;
$base-50: #F1F2FE;
$base-100: #DADCFB;
$base-200: #B8BBF5;
$base-300: #878CE8;
$base-400: #5B61D7;
$base-500: #383FBC;
$base-600: #323790;
$base-700: #292C66;
$base-800: #1E2042;
$base-900: #141529;
$base-hover: #111676;
$base-subtle: #AFB1E9;

{
    "color": {
        "base": {
            "value": "#151B91",
            "type": "color"
        },
        "onBase": {
            "value": "#FFFFFF",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F1F2FE",
                "type": "color"
            },
            "100": {
                "value": "#DADCFB",
                "type": "color"
            },
            "200": {
                "value": "#B8BBF5",
                "type": "color"
            },
            "300": {
                "value": "#878CE8",
                "type": "color"
            },
            "400": {
                "value": "#5B61D7",
                "type": "color"
            },
            "500": {
                "value": "#383FBC",
                "type": "color"
            },
            "600": {
                "value": "#323790",
                "type": "color"
            },
            "700": {
                "value": "#292C66",
                "type": "color"
            },
            "800": {
                "value": "#1E2042",
                "type": "color"
            },
            "900": {
                "value": "#141529",
                "type": "color"
            }
        }
    }
}

Palettes built on #151B91

Color Lab

Pairs with #151B91

UI roles & guardrails

In real applications

Scales

Every model

Export