No matter how great your email's content is, if it renders badly on the reader's device, they'll close it right away. Even worse, wrong parameters can send the email straight to spam. To avoid that and make your campaign work well, you should keep an eye on the size of every block in the email.

In this article, we cover what the right email and all its elements should look like.

Optimal template size

For an email to fit fully on a smartphone or laptop screen, you should stick to a width of 600 pixels. This is the standard parameter that looks great on almost any device.

If you make the email wider, the user will have to scroll it horizontally to see the full content. Because of this extra action, the completion read rate of the campaign will be lower, while the unsubscribe or spam complaint rate will be higher. So it's better not to experiment and stick to more standardized templates.

There are no strict limits on email height. We recommend aiming for 1500–2000 px. That's enough to convey all the necessary information without overloading the user with excess content.

Subject line size

The first thing a subscriber sees when they receive a campaign is the subject line. It's what attracts the user and prompts them to open the email. The subject should convey the most important information. For promotional emails, it's best to highlight the benefit the reader will get, for example "30% off everything" or "A gift with purchases over $30".

According to statistics, most users read their email on a smartphone. So the subject line length should be around 30 characters. Otherwise the text will get cut off.

Preheader and header sizes

The preheader is the text that appears in the first block of an opened email and after the subject line in the preview area. The optimal size for it is up to 70 px and up to 140 characters. The preheader shouldn't grab all of the user's attention, so it's best not to make it too large.

For the header, which contains the logo, the menu, or both, it's best to use a size of 150–200 pixels. Smaller and you won't be able to display all the elements nicely; larger and you'll take up almost the whole screen and distract the reader from the main content of the email.

Banner size

A banner in a campaign can be either horizontal or vertical. You can place it anywhere in the email: after the header, in the middle, or before the CTA button. The main thing is that the banner fits on the device's screen. For this, its width should be no more than 600 pixels, ideally 300–400 pixels. Height, in this case, is likewise unrestricted.

The most common banner sizes are 600×300 or 400×400. For convenience, you can use these as a reference.

Image size

For an image to display perfectly in an email client and load fast, you should stick to a width of up to 600 pixels and a height of around 500 pixels.

We recommend not using overly "heavy" images. There are 2 reasons for this:

  • No one will appreciate high image quality — email clients cut down the quality anyway.
  • Such images will take a long time to load.

Footer size

The footer usually contains a company's social media icons, contact information, and an unsubscribe link. A block of 600 by 200 pixels is enough for this. But if you need to fit a privacy policy, a menu, or other elements in the footer, the height can be greater — up to 1000 pixels.

Text block size

Like other blocks, the text block should be up to 600 pixels wide. For that block width, around 75 characters per line is optimal. This way the text will display correctly on any device without jumping from one line to another and ruining the visual layout.The height of the text block is up to you. The main thing is not to overload the email.

Call-to-action button size

There are no universally accepted standards here. The button can vary: a 46×46 square or a 120×60 rectangle. Base it on the button's content (a word or short phrase) and choose dimensions so the text doesn't overflow the element.

Email size for an email campaign

For an email to load quickly regardless of the user's internet speed, its weight should stay within 100 kilobytes. This limit applies to most email clients.

A handy cheat sheet