What color is #166FF4?

#166FF4 is a medium, vivid blue. In RGB it is rgb(22, 111, 244), and in HSL hsl(216, 91%, 52%).

Is #166FF4 accessible as text?

On white, #166FF4 has a contrast ratio of 4.55:1 (passes WCAG AA for body text); on black it is 4.61:1 (passes). For text placed on #166FF4, use black for the best readability.

What is the closest Tailwind color to #166FF4?

The nearest Tailwind CSS token is blue-600 (#155DFC).

What colors go well with #166FF4?

#166FF4 pairs cleanly with neutrals — cream, taupe, charcoal and cool grays — and with its complementary #F49B15. In UI, a softer accent is often easier to use than the exact complement. Explore the harmonies, shades, tints and ready-made palettes for #166FF4 below.

Is #166FF4 good for buttons?

#166FF4 works for buttons; black text has the higher contrast, so prefer it for labels.

Is #166FF4 the same as CSS royalblue?

No — #166FF4 is not the CSS named color royalblue, but royalblue (#4169E1) is the closest CSS named color.

#166FF4 Color — HEX, RGB, HSL, Palette & Shades

Palettes built on #166FF4

Not just a swatch — here's how #166FF4 works with other colors. Named schemes with #166FF4 in its natural role, and a note on why the supporting colors balance it.

Tech Product Signal · 5 colors

Signal #166FF4 Surface #14161A Highlight #F4F6F8 Secondary #5A6672 Accent #4E98FF

Royal 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 Royal Blue.

Coastal Morning Lead · 5 colors

Lead #166FF4 Accent #A5C4C1 Surface #DDDBBF Secondary #9AA0A1 Anchor #20344A

Royal Blue 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 #166FF4 Surface #F6E5D8 Anchor #5A2144 Accent #E4C2CA Secondary #322B2F

Royal Blue sits between cream and a deep berry here, softened by a blush accent and grounded by charcoal.

Minimal Editorial Surface · 5 colors

Surface #F6F4EF Accent #166FF4 Secondary #87A4D2 Support #9D8F88 Ink #16140F

Royal 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 Royal Blue carrying the quiet middle.

Sunset Warmth Glow · 5 colors

Glow #166FF4 Secondary #E76A76 Accent #F79152 Anchor #573B58 Surface #EEEBD6

Royal Blue 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 #166FF4 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 7/100

Cool

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

Softness 34/100

Low

Middle-weight — neither delicate nor heavy.

Depth 46/100

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 19/100

Very low

Clean and current — no dusty, aged cast.

Luxury 44/100

Moderate

Understated — leans refined without going austere.

Brand distinctiveness 83/100

Very high

Bold and ownable — memorable as a primary brand color.

UI accent fit 77/100

High

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

Surface fit 15/100

Very low

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

Print safety 58/100

Moderate

Prints close, with a slight loss of vibrancy.

Pairs with #166FF4

For UI

For branding

For interior

For fashion

People also use #166FF4 with

Cyan Ultramarine Butterscotch Gainsboro Charcoal

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 4.6:1. Use

Subtle surface Use #D6E3F7 for cards and hover fills. Tint 80

Avoid beside #1524F4 — 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 #166FF4 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: #166FF4;
  --color-base-rgb: 22 111 244;
  --color-base-oklch: oklch(57.4% 0.215 259.7);
  --color-50: #F0F6FE;
  --color-100: #D8E7FD;
  --color-200: #B1CFFB;
  --color-300: #7DACF2;
  --color-400: #4E8AE4;
  --color-500: #2A6ACB;
  --color-600: #28569A;
  --color-700: #23406C;
  --color-800: #1B2C46;
  --color-900: #121C2B;
  --color-on-base: #141310;
}

// tailwind.config.js
colors: {
  royal-blue: {
    50: '#F0F6FE',
    100: '#D8E7FD',
    200: '#B1CFFB',
    300: '#7DACF2',
    400: '#4E8AE4',
    500: '#2A6ACB',
    600: '#28569A',
    700: '#23406C',
    800: '#1B2C46',
    900: '#121C2B',
  },
}

$base: #166FF4;
$base-ink: #141310;
$base-50: #F0F6FE;
$base-100: #D8E7FD;
$base-200: #B1CFFB;
$base-300: #7DACF2;
$base-400: #4E8AE4;
$base-500: #2A6ACB;
$base-600: #28569A;
$base-700: #23406C;
$base-800: #1B2C46;
$base-900: #121C2B;
$base-hover: #0A57CB;
$base-subtle: #C1D5F4;

{
    "color": {
        "base": {
            "value": "#166FF4",
            "type": "color"
        },
        "onBase": {
            "value": "#141310",
            "type": "color"
        },
        "scale": {
            "50": {
                "value": "#F0F6FE",
                "type": "color"
            },
            "100": {
                "value": "#D8E7FD",
                "type": "color"
            },
            "200": {
                "value": "#B1CFFB",
                "type": "color"
            },
            "300": {
                "value": "#7DACF2",
                "type": "color"
            },
            "400": {
                "value": "#4E8AE4",
                "type": "color"
            },
            "500": {
                "value": "#2A6ACB",
                "type": "color"
            },
            "600": {
                "value": "#28569A",
                "type": "color"
            },
            "700": {
                "value": "#23406C",
                "type": "color"
            },
            "800": {
                "value": "#1B2C46",
                "type": "color"
            },
            "900": {
                "value": "#121C2B",
                "type": "color"
            }
        }
    }
}

Palettes built on #166FF4

Color Lab

Pairs with #166FF4

UI roles & guardrails

In real applications

Scales

Every model

Export