#428fbc

Boston Blue

Closest match (96% match)

Color formats

RGB

rgb(66, 143, 188)

Red, Green, Blue components

HSL

hsl(202, 48%, 50%)

Hue, Saturation, Lightness

CMYK

cmyk(65, 24, 0, 26)

Print color encoding

Luminance

0.244

Relative luminance

Variations

Shades (Darkening)

Tints (Lightening)

Tones (Reduced saturation)

Harmonies

Click the color slices to copy the code.

Complementary (Opposite)

#428fbc

#bc6f42

Analogous (Adjacent)

#42bcac

#428fbc

#4252bc

Triadic

#428fbc

#bc428f

#8fbc42

Split complementary

#428fbc

#bc4252

#bcac42

Complete conversion table

HEX

#428FBC

RGB

rgb(66,143,188)

RGBA

rgba(66,143,188, 1)

HSL

hsl(202.13,48.03%,49.8%)

OKLCH (Modern CSS)

oklch(0.62 0.10 237.2)

CSS Variable

--color: #428fbc;

Preview

Readability and Typography

Headline Test

This text demonstrates the reading experience on this background color.

Headline Test

This text demonstrates the reading experience on this background color.

UI Component Set

This is an example alert bar using the selected color.

SOLIDSOFTOUTLINE

Product Mockup

4582 •••• •••• 9018

CARDHOLDER

JOHN DOE

VALID

12/28

Mobile application

Customer support

Hi! How can we help you today?

I love this new color! 😍

Data visualization

Weekly growth

+1,240

12.5%

WED

2,450

Contrast

Contrast and readability (WCAG)

On white background

3.57

Small text (14pt)

The quick brown fox jumps over...

AAA

Large text or UI (18pt Bold)

AAA

On black background

5.89

Small text (14pt)

The quick brown fox jumps over...

AAA

Large text or UI (18pt Bold)

AAA

Color blindness simulator

ORIG

SIM

Protanopia (red)

#428fbc#a3a3bc

ORIG

SIM

Deuteranopia (green)

#428fbc#6e67bc

ORIG

SIM

Tritanopia (blue)

#428fbc#46606b

ORIG

SIM

Monochrome (color blind)

#428fbc#888888

Mixing guide

How to mix this color using physical paints or printing inks.

MIXING PALETTE

84%

16%

RYB PIGMENTS

Ultramarine blue

Pigment

84%

Cadmium yellow

Pigment

16%

Ivory black

Pigment

Unlike light, mixing paints makes colors darker. This simulation mimics the behavior of physical pigments.

Physical properties

Perceptual and light-related properties derived from the digital color.

Spectral relationship

Blue hue

450–495 nm • closest visible-spectrum range

750 nm

380 nm

Visual temperature

Cool

A perceptual warm–cool classification. Kelvin does not apply to an arbitrary interface color.

Cool

Neutral

Warm

Luminance (brightness)

24.4%

Dark • relative luminance

50%

100%

An RGB color is produced by combined screen light, so this range is a visual comparison rather than an exact physical wavelength.

Gradient gallery

Generate premium CSS backgrounds and textures from your color.

Similar & Related Colors

Mathematically computed harmonies, shades, and similar tones for this color.

Swimmer

#0A91BF

Underwater Moonlight

#4488AA

Mermaid Dreams

#0088BB

Forget-Me-Not

#0087BD

Brown Rust

#BC6F42

Indigo

#4252BC

Puerto Rico

#42BCAC

Mulberry

#BC428F

Sushi

#8FBC42

Chestnut

#BC4252

Malibu

#82C9F9

Orient

#005982