Tillitsdone
down Scroll to discover

CSS Width A Comprehensive Guide for Web Design

Discover the CSS width property, its use cases, and available options.

Learn how to set element widths using pixels, ems, and percentages.

Create responsive designs.
thumbnail

The width property in CSS sets how wide an element is. It can be the content area or the border area, depending on the box-sizing property. This property is crucial for creating responsive designs that look good on different devices and screen sizes.

How width Works

  • Default Behavior: By default, width sets the width of the content area. If box-sizing is set to border-box, it sets the width of the border area.
  • Constraints: The width property is subject to min-width and max-width. If width is less than min-width, min-width takes over. If width is greater than max-width, max-width takes over.
  • SVG Elements: width also applies to SVG elements like <svg>, <rect>, <image>, and <foreignObject>. For instance, auto resolves to 100% for <svg> and 0 for other elements, and percent values are relative to the SVG viewport width for <rect>.

Example

Here’s a simple example to demonstrate the use of the width property:

<!DOCTYPE html>
<html>
<head>
<title>CSS width Property</title>
<style>
.auto-width {
width: auto;
color: white;
font-size: 20px;
background-color: rgb(0, 150, 0);
}
h2 {
font-size: 20px;
color: black;
}
</style>
</head>
<body>
<h2>CSS width Property</h2>
<p class="auto-width">
This is an example of the auto width property.
</p>
</body>
</html>

In this example, the paragraph with the class auto-width will have its width automatically calculated by the browser, making it flexible and adaptive to different content and screen sizes.

Using initial

The width: initial property sets an element’s width to its default value. This resets the width to its original state, ignoring any previously applied width styles.

<!DOCTYPE html>
<html>
<head>
<title>CSS width Property</title>
<style>
.initial-width {
width: initial;
color: white;
font-size: 20px;
background-color: rgb(0, 150, 0);
}
h2 {
font-size: 20px;
color: black;
}
</style>
</head>
<body>
<h2>CSS width Property</h2>
<p class="initial-width">
This is an example of the initial width property.
</p>
</body>
</html>

Units: Pixels and Ems

You can set the width of an element using pixels (px) and ems (em). Pixels are fixed, while ems are relative to the font size.

.px-width {
width: 200px;
background-color: red;
color: white;
border: 1px solid black;
}
.em-width {
width: 20em;
background-color: white;
color: red;
border: 1px solid black;
}

Example using max-content

The max-content value sets the width of an element to its intrinsic preferred width.

p.max-content {
background: lightgreen;
width: max-content;
}

And the HTML:

<p class="max-content">The MDN community writes really great documentation.</p>

Formal Definition

  • Initial Value: auto. The browser calculates the width based on content and available space.
  • Applies To: All elements except non-replaced inline elements, table rows, and row groups.
  • Inherited: No.
  • Percentages: Relative to the width of the containing block.
  • Computed Value: Can be a percentage, auto, or an absolute length.
  • Animation Type: Can be animated using length, percentage, or calc() values.

Specifications

The width property is defined by the CSS Box Sizing Module Level 4 and the CSS Sizing Module Level 4.

See Also

  • [The box model]WebsiteUrl: Learn about the CSS box model.
  • [height]WebsiteUrl: Explore the height property.
  • [box-sizing]WebsiteUrl: Understand how box-sizing affects the calculation of an element’s width and height.
  • [min-width]WebsiteUrl and [max-width]WebsiteUrl: Set minimum and maximum width constraints.
  • [Mapped logical properties: block-size and inline-size]WebsiteUrl: More flexible control of element dimensions.
  • [anchor-size()]WebsiteUrl: Set the size of an element relative to an anchor element.

These resources will help you use the width property effectively to create responsive and visually appealing web designs.

icons/logo-tid.svg Latest Blogs
Discover our top articles, selected to support the growth of your business.
https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R43_Sep_1440x697.jpg@webp สร้างเว็บไซต์ 1 เว็บ ต้องใช้งบเท่าไหร่? เจาะลึกทุกองค์ประกอบ website development cost อยากสร้างเว็บไซต์แต่ไม่มั่นใจในเรื่องของงบประมาณ อ่านสรุปเจาะลึกตั้งแต่ดีไซน์, ฟังก์ชัน และการดูแล พร้อมตัวอย่างงบจริงจาก Till it&#8217;s done ที่แผนชัด งบไม่บานปลายแน่นอน https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R42_Sep_1440x697.jpg@webp Next.js สอน 14 ขั้นตอนเบื้องต้น: สร้างโปรเจกต์แรกใน 30 นาที เริ่มต้นกับ Next.js ใน 14 ขั้นตอนเพียงแค่ 30 นาที พร้อม SSR/SSG และ API Routes ด้วยตัวอย่างโค้ดง่าย ๆ อ่านต่อเพื่อสร้างโปรเจ็กต์แรกได้ทันทีที่นี่ https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R41_Sep_1440x697.jpg@webp วิธีสมัคร Apple Developer Account เพื่อนำแอปขึ้น App Store ทีละขั้นตอน อยากปล่อยแอปบน App Store ระดับโลก มาอ่านคู่มือสมัคร Apple Developer Account พร้อมเคล็ดลับ TestFlight และวิธีอัปโหลดที่ง่ายในบทความเดียวนี้ได้เลย https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R38_Sep_1440x697.jpg@webp TypeScript Interface คืออะไร? อธิบายพร้อมวิธีใช้และข้อแตกต่างจาก Type เรียนรู้วิธีใช้ TypeScript Interface เพื่อสร้างโครงสร้างข้อมูลที่ปลอดภัยและเข้าใจง่าย พร้อมเปรียบเทียบข้อดีข้อแตกต่างกับ Type ที่คุณต้องรู้ ถูกรวมเอาไว้ในบทความนี้แล้ว https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F09%2FTill-its-done_SEO_R36_Sep_1440x697.jpg@webp Material-UI (MUI) คืออะไร อยากสร้าง UI สวยงามและเป็นมืออาชีพในเวลาอันรวดเร็วใช่ไหม มาทำความรู้จักกับ Material-UI (MUI) ที่ช่วยให้คุณพัฒนาแอปพลิเคชันบน React ได้ง่ายและดูดีในทุกอุปกรณ์ https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F09%2FTill-its-done_SEO_R27_Sep_1440x697.jpg@webp เปรียบเทียบ 3 วิธีติดตั้ง install node js บน Ubuntu: NVM vs NodeSource vs Official Repo แบบไหนดีที่สุด? เรียนรู้วิธีติดตั้ง Node.js บน Ubuntu ด้วย NVM, NodeSource หรือ Official Repo เลือกวิธีที่เหมาะกับความต้องการของคุณ พร้อมเปรียบเทียบ เพื่อการพัฒนาที่มีประสิทธิภาพ!
icons/logo-tid.svg

Talk with CEO

Ready to bring your web/app to life or boost your team with expert Thai developers?
Contact us today to discuss your needs, and let’s create tailored solutions to achieve your goals. We’re here to help at every step!
🖐️ Contact us
down Explore our best articles, cover a wide variety of technologies
Our knowledge base
196 Articles
Explore right
icons/logo-react.svg ReactJs
Popular JavaScript library for building user interfaces with a component-based architecture.
160 Articles
Explore right
icons/flutter.svg Flutter
UI toolkit for building natively compiled applications for mobile, web, and desktop from a single codebase.
144 Articles
Explore right
icons/logo-nodejs.svg Nodejs
JavaScript runtime for building scalable, high-performance server-side applications.
58 Articles
Explore right
icons/next-js.svg Nextjs
React framework enabling server-side rendering and static site generation for optimized performance.
38 Articles
Explore right
icons/tailwind.svg TailwindCSS
Utility-first CSS framework for rapid UI development.
36 Articles
Explore right
icons/code-outline.svg Typescript
Superset of JavaScript adding static types for improved code quality and maintainability.
126 Articles
Explore right
icons/code-outline.svg Golang
Programming language known for its simplicity, concurrency model, and performance.
67 Articles
Explore right
icons/code-outline.svg AstroJs
Astro is an all-in-one web framework. It includes everything you need to create a website, built-in.
38 Articles
Explore right
icons/code-outline.svg Jest
Versatile testing framework for JavaScript applications supporting various test types.
16 Articles
Explore right
icons/code-outline.svg Website development th
11 Articles
Explore right
icons/code-outline.svg Mobile application th
5 Articles
Explore right
icons/code-outline.svg Reactjs th
4 Articles
Explore right
icons/code-outline.svg Nextjs th
3 Articles
Explore right
icons/code-outline.svg Flutter th
1 Articles
Explore right
icons/code-outline.svg Software house th
1 Articles
Explore right
icons/code-outline.svg Nodejs th
1 Articles
Explore right
icons/code-outline.svg Typescript th
337 Articles
Explore right
icons/css-4.svg CSS
CSS3 is the latest version of Cascading Style Sheets, offering advanced styling features like animations, transitions, shadows, gradients, and responsive design.
Let's keep in Touch
Thank you for your interest in Tillitsdone! Whether you have a question about our services, want to discuss a potential project, or simply want to say hello, we're here and ready to assist you.
We'll be right here with you every step of the way.
Contact Information
rick@tillitsdone.com+66824564755
Find All the Ways to Get in Touch with Tillitsdone - We're Just a Click, Call, or Message Away. We'll Be Right Here, Ready to Respond and Start a Conversation About Your Needs.
Address
9 Phahonyothin Rd, Khlong Nueng, Khlong Luang District, Pathum Thani, Bangkok Thailand
Visit Tillitsdone at Our Physical Location - We'd Love to Welcome You to Our Creative Space. We'll Be Right Here, Ready to Show You Around and Discuss Your Ideas in Person.
Social media
FacebookInstagramLinkedIn
Connect with Tillitsdone on Various Social Platforms - Stay Updated and Engage with Our Latest Projects and Insights. We'll Be Right Here, Sharing Our Journey and Ready to Interact with You.
We anticipate your communication and look forward to discussing how we can contribute to your business's success.
We'll be here, prepared to commence this promising collaboration.
Frequently Asked Questions
Explore frequently asked questions about our products and services.
Whether you're curious about features, warranties, or shopping policies, we provide comprehensive answers to assist you.