Most people check their emails on their phones before they do anywhere else. This means that if your emails are not designed with mobile in mind, you risk losing clicks, conversions and attention. A mobile-first approach makes sure your emails look great, load quickly and are easy to read on any screen.

Why mobile-first matters

Over 60% of emails are opened on a mobile device. If your design only works well on desktop, you are alienating the majority of your audience. A mobile-first approach ensures that your emails are:

• Easy to read without pinching and zooming
• Quick to load on mobile networks
• Designed with clear calls to action that are simple to tap
• Accessible to people wherever they are

Key principles of mobile-first email design

Keep it simple

On a smaller screen, cluttered layouts become overwhelming. Stick to one main goal per email, use short paragraphs and avoid cramming in too much content.

Use a single column layout

Multi-column designs often break on small screens. A single column layout ensures your content flows naturally and remains easy to read.

Prioritise your call to action

Make buttons big enough to tap with a thumb and position them where they can be easily found. Use clear wording such as “Shop now” or “Download the guide.”

Choose mobile-friendly fonts

Use fonts that are legible at smaller sizes. Aim for at least 14px for body text and 22px or larger for headlines.

Optimise images

Large images can slow loading times on mobile. Use compressed files and include alt text so that your message is still clear even if images do not load.

Testing your emails on mobile

When editing the content of your email, you will notice just above the creative editor there is a “Desktop/Mobile” slider in both Klaviyo and Mailchimp. Here you can see exactly how your email will appear on a phone screen. We highly recommend building and editing directly in this view so mobile users see your message in the best light.

We also recommend sending yourself and your colleagues a preview before scheduling to see how the email looks in your actual inbox across different email providers, such as Outlook and Gmail. This gives you a realistic view of how subscribers will experience your message and allows you to make final adjustments.

Mobile-first best practices

• Put the most important content at the top so it is seen straight away.
• Use plenty of white space to make text easy to read.
• Keep subject lines and preheader text short so they display properly on smaller screens.
• Avoid tiny links or text-based calls to action that are difficult to tap.

Final thoughts

Designing emails with mobile in mind is no longer optional. With most subscribers opening on their phones, clarity, simplicity and strong calls to action are essential. Use the mobile preview in your platform while editing, send yourself test emails and always check how your campaigns look in real inboxes. By making mobile-first design a habit, you will ensure your emails are clear, effective and engaging wherever they are opened.