The magic email newsletter length calculator
A lot of time and effort goes into creating email newsletters and marketing campaigns. So you want to make sure that they’re worth the effort, right?
Will your newsletters and campaigns actually be read by the people you send them to?
I expect you’re creating your email campaigns on a desktop, right? There’s a good chance the people you send them to are viewing them on a mobile though.
One line on your desktop is usually about three lines on a mobile. That means that, what looks like a short email on your desktop, can quickly become very long on their mobile.
More lines = more thumb scrolls = more effort to get to the main point and act on your CTA (Call to Action).
So, try this handy calculator before you send an email – it might make you think differently…
How long will your Mailchimp email be for mobile users?
You're creating your Mailchimp email on your desktop. But chances are at least 50% of recipients will be opening it on a mobile. Does it still work? Use this quick calculator to check.
What will your Mailchimp subject line look like on mobile?
Let's see where it will be cropped
Approximate preview of your subject line on a mobile screen:
…
Is your subject line still effective when it's cropped?
Safe zone: This part of your subject line is likely to be visible on mobile.
Risky zone: This part might not be visible, depending on the inbox and device.
And how long will your Mailchimp email be when it's read on a mobile?
- Silent read time (assuming no distractions):
- Desktop length:
- lines
- Mobile length:
- lines
- Mobile scrolling:
- thumb scrolls
Very short on mobile – great for quick announcements or a single, clear call to action. But check if your email is too short and abrupt, especially on desktop.
It sounds like this will be quick and easy to read on both mobiles and desktops. Check for font size and make sure you're using headings to make it easy to skim read.
Comfortable but focused read. Readers will need a bit of attention, but it should still feel manageable on mobile too.
It's getting on the long side, especially for mobile users. Best for readers who are already interested or intentionally opening your email, otherwise be careful and consider if this is the best way to do it.
This sounds like a lonnnnng email. It probably won't be read in full whatever device they're using. Is this the best way to do it?
5 ways to make short emails more compelling Read this first to be on the safe side Tips for structuring longer emails Read this before you sendA note about longer emails
Longer emails can hit email client limits. Gmail, for example, crops emails that are over 102 KB and inserts a "View entire message" link. So, make sure your primary message and call to action are near the top.
How these estimates work
- Reading time assumes an average silent reading speed of 250 words per minute. It may be longer with distractions when on mobile for example.
- Line counts are based on typical Mailchimp formatting using a single-column layout.
- Mobile emails are estimated to display ~3× more lines than desktop
- Images are estimated to add ~10 lines on desktop and ~5–6 lines on mobile.
- Assumes images are decorative and not infographics containing text (if they are, we need to talk!)
- Thumb scrolls are based on an average of ~9–10 visible lines per mobile screen.
- Estimates assume standard paragraph font size and exclude additional lines created by large headings and white space.
- Email subject preview uses an approximate benchmark: the first 35 characters are likely to be visible, while subject lines longer than 50 characters may be cropped. Actual visibility varies by device, screen size, email app, sender name and inbox settings.
These figures are intended as practical estimates, not exact measurements, and will vary by device, formatting, and reader behaviour.