Tints & Shades
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Scale from white (50) through Blue (500) to black (900), interpolated in Lab color space.
Color Values
- HEX
- #0000FF
- RGB
- rgb(0, 0, 255)
- HSL
- hsl(240, 100%, 50%)
- OKLCH
- oklch(0.452 0.313 264)
- CMYK
- cmyk(100%, 100%, 0%, 0%)
--color-bluebg-[#0000FF]Accessibility
Score: 96/100On White (#FFF)
8.59:1
On Black (#000)
2.44:1
On Light Gray (#F5F5F5)
7.88:1
Best text color on this background:
Design Applications
background-color: #0000FF
color: #0000FF
bg-[#0000FF] text-[#FFFFFF]
border-left: 4px solid #0000FF
Color Harmonies
Similar Colors
Color Meaning & Psychology
Pure blue activates the mind's analytical capabilities and slows physiological arousal — the opposite of red. It is the color of information technology (IBM's "Big Blue"), of social networks (Facebook, Twitter), and of the entire concept of trust in digital commerce. Pure blue is rare in nature except the sky and ocean, giving it an open, unlimited feeling.
Industry Usage
Common contexts and industries where Blue is applied in professional design.
- Banking, insurance, and financial institutions
- Healthcare and medical device companies
- Enterprise software and SaaS platforms
- Government and public sector organizations
- Airlines and aviation brands
- Communication and social networking apps
- Cybersecurity and data protection products
- Pharmaceutical companies and clinical products
Accessibility Considerations
Normal Text
Passes AA
4.5:1 minimum required
Large Text
Passes AA Large
3:1 minimum required
UI Components
Meets 1.4.11
3:1 for non-text UI
Blue is a dark color. Use white (#FFFFFF) text on top of it for maximum readability (8.59:1). Avoid small black text on this background.
CSS & Code Examples
Background
background-color: #0000FF;Text
color: #0000FF;Border
border: 2px solid #0000FF;Box Shadow
box-shadow: 0 4px 20px #0000FF40;Gradient
background: linear-gradient(135deg, #0000FF, #7142ff);Tailwind-style
--color-blue: #0000FF;Tailwind CSS Utilities
Use arbitrary value syntax in Tailwind CSS to apply Blue without a custom config.
Background
bg-[#0000FF]Text
text-[#0000FF]Border
border-[#0000FF]Ring
ring-[#0000FF]Fill
fill-[#0000FF]From (gradient)
from-[#0000FF]Via (gradient)
via-[#0000FF]To (gradient)
to-[#0000FF]Design Tokens
Ready-to-use Blue design token in CSS custom properties, SCSS, Tailwind v3/v4, and JSON formats.
CSS Custom Properties
:root {
--color-blue: #0000FF;
--color-blue-rgb: 0, 0, 255;
--color-blue-hsl: 240, 100%, 50%;
}SCSS Variables
$color-blue: #0000FF; $color-blue-rgb: 0, 0, 255; $color-blue-hsl: 240, 100%, 50%;
Tailwind v3 Config
// tailwind.config.js
module.exports = {
theme: {
extend: {
colors: {
'blue': '#0000FF',
},
},
},
};Tailwind v4 (@theme)
/* tailwind.css */
@theme {
--color-blue: #0000FF;
}JSON Design Token (W3C format)
{
"blue": {
"value": "#0000FF",
"type": "color",
"description": "Blue — #0000FF"
}
}More blue colors
View all →What Does Blue Mean? Color Psychology & Cultural Symbolism
The reason Blue projects reliability is partly evolutionary (blue skies and clean water = safety) and partly cultural (centuries of professional, governmental, and institutional use have trained associations). The result is a color that creates instant psychological permission to engage.
- Across color psychology research, blue consistently tests high for "trustworthiness" associations, making Blue a reliable vehicle for reliability in cross-demographic audiences.
- Brand designers draw on blue-family tones to project stability and competence—values that Blue communicates in a medium key.
- At 100% saturation, Blue reads as vivid—Electric and royal blues are modern, confident, and digitally native—they signal tech-forward positioning and work well for startups challenging traditional industries.
- Blue's medium lightness (50%) shifts its psychological register: a balanced mid-tone that embodies trust, reliability, calm, and professionalism at its most direct.
In a world of visual noise, Blue earns attention through steadiness. Use it where you need to be believed.
How to Use Blue in Design: Applications, Pairings & Best Practices
Blue's accessibility profile makes it one of the more designer-friendly choices in the warm-cool spectrum. Its medium quality at 50% lightness typically produces workable contrast ratios for both text and UI applications.
- Avoid: food contexts where it suppresses appetite (the only major color with no natural blue foods), extreme urgency signals, and applications targeting very young children where warmer colors perform better.
- Color harmonies: Blue's complementary color creates a high-energy split ideal for promotional design; its analogous palette (±30° hue) builds cohesive, monochromatic sophistication.
- Proportional use: Blue's vivid saturation (100%) means small applications—accents, highlights, icons—deliver maximum impact without visual fatigue. Reserve large-scale use for intentional brand moments.
- As a dark tone, Blue creates maximum contrast with white and light neutrals—excellent for creating premium dark-mode sections, bold headers, and high-drama brand moments
- Typography: Blue works as a background behind white text but requires careful sizing—test at intended heading and body sizes before finalizing.
In a world of visual noise, Blue earns attention through steadiness. Use it where you need to be believed.
Blue Accessibility: WCAG Contrast Ratios, Color Blindness & Inclusive Design
Blue (#0000FF) achieves a 8.59:1 contrast ratio with white text, surpassing the WCAG 2.1 AAA threshold of 7:1. This exceptional contrast qualifies it for body text, UI components at any size, and all accessibility-sensitive interface contexts. Relative luminance: 7.2%.
- As text on white (#FFFFFF): 8.59:1 — AAA ✓
- As text on black (#000000): 2.44:1 — Fail
- Best text color on Blue background: White (#FFFFFF) at 8.59:1
- WCAG 2.1 luminance: 7.2% — low luminance (dark)—it provides strong contrast for white and light overlaid text, functioning well as a background in dark-mode and header contexts
- Blue qualifies for all text sizes including small body copy (AAA).
- Color blindness consideration: tritanopia (blue-yellow color blindness, ~0.003% of population) may affect how this color reads. While rare, for maximum accessibility supplement color signals with text or icon indicators in critical states.
Blue's WCAG profile makes it a compliant choice for most text applications.
Blue in Industry: Branding, Design & Market Applications
Blue (#0000FF) is most at home in industries where trust, reliability, calm, and professionalism are key brand values. Its medium quality makes it particularly effective in Finance & Banking contexts, where the vivid saturation signals trust at exactly the right register.
- Finance & Banking: Blue is the most trusted color in financial services—a global design convention built over decades. It signals fiduciary reliability, stability, and the conservative stewardship that depositors and investors need to feel comfortable transferring wealth. (examples: Capital One, PayPal, Visa) Dark navy communicates established tradition; mid-tone blues suggest accessible, modern banking. Avoid pure bright blue for legacy institutions.
- Technology: Technology brands use blue to communicate intelligence, reliability, and forward-thinking professionalism. From legacy enterprise software to consumer apps, blue provides a neutral credibility that scales across markets and cultures. (examples: Notion, Slack, Salesforce) Varying the tone of blue is how tech brands differentiate: sky blue for friendliness (consumer apps), royal blue for confidence (productivity tools), navy for enterprise seriousness.
- Healthcare: Healthcare's use of blue is a trust transfer from corporate credibility to clinical reliability. Patients associate blue with cleanliness, precision, and medical competence—making it the second most common healthcare color after white. (examples: Headspace, One Medical, Kaiser Permanente) Teal-blue works particularly well for health tech and telemedicine, balancing clinical trust with digital accessibility.
- Brand positioning: Blue is best suited for brands projecting stability, competence, professionalism. Categories outside this positioning—food contexts where it suppresses appetite (the only major color with no natural blue foods)—tend to see weaker results.
- Adjacent applications: Beyond primary industries, Blue works effectively in trust-critical applications, government services, B2B software—contexts where trust serves a secondary but reinforcing role.
The industries where Blue performs best are those where the audience expects trust. Build brand strategy around this alignment, not against it.
Accessibility & Design Guides
Frequently Asked Questions
- What is the hex code for Blue? ▾
- The hex code for Blue is #0000FF. Its RGB values are rgb(0, 0, 255) and its HSL values are hsl(240, 100%, 50%).
- What does Blue mean in design? ▾
- Pure blue activates the mind's analytical capabilities and slows physiological arousal — the opposite of red. It is the color of information technology (IBM's "Big Blue"), of social networks (Facebook, Twitter), and of the entire concept of trust in digital commerce. Pure blue is rare in nature except the sky and ocean, giving it an open, unlimited feeling.
- Is Blue WCAG accessible? ▾
- Blue (#0000FF) passes WCAG AAA on white with a 8.59:1 contrast ratio. Its overall accessibility score is 96/100.
- What colors go well with Blue? ▾
- Blue pairs well with its complementary color Yellow (#FFFF00). Analogous colors like Bleu de France and Royal Blue also work harmoniously. Check the Color Harmonies section above for the full palette.
- What is Blue used for? ▾
- Blue is commonly used for: Banking, insurance, and financial institutions; Healthcare and medical device companies; Enterprise software and SaaS platforms; Government and public sector organizations; Airlines and aviation brands.
- What are the CSS and Tailwind values for Blue? ▾
- In CSS, use `color: #0000FF` or `background-color: #0000FF`. The CSS custom property is `--color-blue: #0000FF`. In Tailwind CSS, use the arbitrary value class `bg-[#0000FF]` for backgrounds or `text-[#0000FF]` for text.