Font size guidelines for responsive web design refer to best methods for setting text sizes that are easy to read and use on different screen sizes, such as desktops, tablets and smartphones. The goal is to ensure that text always remains clear and accessible regardless of the device being used.

Why font size is essential as part of your corporate identity design 

Font size plays a crucial role in the design of your corporate identity and helps determine how your brand is perceived. It's not just about legibility, but also about appearance, recognition and consistency in your communication.

1. Brand identity and appearance 

The font size chosen affects how professional and approachable your brand looks. For example, large, bold letters exude modernity and creativity, while smaller, more subtle sizes can give an elegant and sophisticated look.

2. Consistency in communication 

An established typography with clear guidelines for font sizes (for example, for headlines, subheads and body text) creates a recognizable brand experience. This helps with the recognition of your brand on websites and social media.

3. User experience and accessibility 

Font sizes that are too small or irregular can make your brand look disjointed and unprofessional. By choosing well-tuned font sizes that fit your target audience, you ensure that your message comes across clearly across all platforms and devices.

What is a good basic font size for web texts? 

A good basic font size for Web text is 16 pixels (px) or 1 rem. This is often used as a standard because it provides comfortable readability on most screens.

Why 16px as a base? 

• Easily readable on desktops and mobile devices without zooming in.

• Consistent with browsers: most web browsers use 16px as the default font size.

• Flexibly scalable: CSS units such as rem and em make it easy to adapt text to different screen sizes.

When bigger or smaller? 

• For long texts (such as blog posts), 18px or 20px may be better for readability.

• Small UI elements (such as labels or buttons) may require a smaller size, but never below 12px.

Figure 1 Font sizes for your website 

What is the difference between px, em and rem ? 

1. px (pixels) - Fixed size 

Pixels are a fixed size. If you set a text to 16px, it will always remain 16 pixels in size regardless of the device or the user's settings. This makes for a predictable display, but makes it less flexible.

2. em - Depending on the parent element 

em adjusts based on the font size of the parent element. Suppose a section of your website has a font size of 20px and you set a header to 1.5em, the text will be 30px (1.5 × 20px). This makes the text flexible.

3. brake - Relative to the base font size 

rem is similar to em, but is always based on the website's capital letter size (usually 16px). A text of 2rem is then 32px (2 × 16px), no matter where it is on the page. This makes rem ideal for consistent text sizes.

Conclusion and recommendations 

A well-chosen font size is essential to both the readability and brand experience of your website. By taking responsive web design into account, you ensure that your texts remain legible on all devices.

Key insights: 

• A base font size of 16px or 1rem is a safe and accessible choice.

• Use rem or em instead of px to ensure flexible and scalable display.

• Consistency in font sizes contributes to a professional corporate identity and better user experience.

• Keep context in mind: longer texts are better off being slightly larger, while small UI elements should never be too small.

Recommendations: 

• Use rem for global texts so that they remain consistent and scalable.

• Handle em for internal components that need to adapt to their container.

• Avoid font sizes that are too small (under 12px) to ensure readability and accessibility.

• Test your design on different devices to make sure the text is always legible.