Last Updated on September 19, 2023 by Mayank Dham

Font size is an important aspect of web design. It determines how text is displayed on a web page and affects the readability and overall look and feel of the design. Font size in CSS is a property that allows designers to adjust the size of the text. In this article, we will explore the various aspects of font size in CSS, including its syntax, properties, and best practices for using it effectively.

Syntax of Font Size
The font size property in CSS has the following syntax:

font-size: value;

value can be specified as a length value, such as px, em, rem, or %. It can also be specified using keywords, such as medium, small, large, or inherit.

Relative and Absolute Font Sizes

There are two types of font sizes in CSS: relative and absolute.

Relative Font Size

Relative font sizes are specified using relative length units, such as em and rem. These units are relative to the font size of the parent element or the root element, respectively.

Example of Relative Font Size:
In this example, we will use rem as a length unit and see the result of the output

HTML Code:

This is heading 1
This is heading 2
This is a paragraph.

Output:

Absolute Font Size

Absolute font sizes are specified using absolute length units, such as px. These units are fixed and do not change based on the font size of the parent or root element.

Example of Absolute Font Size

HTML Code

This is heading 1
This is heading 2
This is a paragraph.
This is another paragraph.

Output

Best Practices to use Font-Size

When using font size in CSS, it’s important to keep a few best practices in mind:

• Choose font sizes that are appropriate for the content and context. For example, larger font sizes may be appropriate for headings, while smaller font sizes may be appropriate for body text.
• Test the font size in different browsers and on different devices to ensure that it is readable and displays correctly.
• Consider using a responsive design approach that adjusts the font size based on the device or screen size.
• Avoid using too many different font sizes in a design, as it can make the design look cluttered and confusing.
• Use relative font sizes, such as em or rem, to make the design more flexible and responsive.

Conclusion
In conclusion, font size is an important part of web design that affects the readability and overall look and feel of the design. In this article, we have learned about font size and also about relative and absolute font sizes and learned them with the help of examples. By choosing appropriate font sizes, testing the design in different browsers and devices, and using best practices, designers can create designs that are readable, effective, and aesthetically pleasing.

FAQs related to Font Size in CSS

Here are some frequently asked questions (FAQs) related to font size in CSS:

Q1. What are the units for specifying font size in CSS?
CSS allows you to specify font size using various units, including pixels (px), ems (em), rems (rem), percentages (%), and more. Each unit has its own characteristics and use cases.

Q2. What’s the difference between px, em, and rem for font size?
px (pixels) is an absolute unit and provides a fixed size, unaffected by the parent element’s font size.
em is a relative unit and is based on the font size of the parent element. It can compound when nested.
rem is also a relative unit but is based on the root (html) element’s font size, making it more predictable for responsive design.

Q3. What’s the recommended font size for websites?
There’s no one-size-fits-all answer, as the ideal font size depends on various factors such as design, readability, and user preferences. However, a common practice is to set the base font size to around 16px and adjust from there.

Q4. How can I make text responsive to different screen sizes?
To make text responsive, you can use relative units like em, rem, or percentages for font sizes. Additionally, you can use media queries to adjust font sizes for different screen sizes.

Q5. Can I use custom fonts with CSS font size?
Yes, you can use custom fonts with CSS. You would typically use the @font-face rule to define a custom font and then apply it to elements along with specifying the font size.

Q6. Is it possible to change the font size of only certain parts of text within an element?
Yes, you can change the font size of specific parts of text within an element by wrapping that text in HTML elements (like < span >) and applying CSS styles to those elements.