More than a third of consumers (36%) read marketing emails on mobile, according to new research .

According to digital agency Steel, this rises to 55% among 18-34 year olds, highlighting the fact that brands need to optimise their email marketing for mobile devices.

The stats are supported by a Knotice study we reported in April which found that 27% of emails are opened on mobile devices.

Steel’s report found that almost 40% of those who read emails on mobile said they did so if the subject line sounded interesting.

The basic rules of email marketing still apply on mobile, “but we need to be smart in how this translates to a mobile version of an email – fewer characters on a far more personal device”.

A third of respondents (33%) said that they use their mobile to screen emails, before reading them later on a desktop, though this does contradict the Knotice stats, which found that in 95% of the cases,  the email open is occurring on only one type of device, which removes one excuse not to optimise for mobile.

Data included in an infographic from Return Path shows that 41% of Europeans would either close or delete an email not optimised for mobile.

However, stats from our Email Marketing Census 2012 found that with 39% of companies said their mobile email strategy was “non-existent”, and 37% said their strategy was “basic”.

Therefore it seems a huge number of brands are wasting a lot of effort and missing out on conversions simply because they haven’t optimised their emails for mobile.

The importance of an effective mobile email campaign is further underlined by engagement statistics form Steel’s report. Among those who open emails on a mobile, 42% of respondents have clicked through to a website and 30% claim to have made a purchase from a mobile email.

In reality 30% seems quite high, but it does suggest that a significant proportion of consumers are encouraged to make purchase decisions from mobile marketing.

Steel recommends the following five steps to improve your mobile email messages:

  • Simplify your emails: reduce the number of categories, sub-headings, links and images.
  • Limit your calls to action and make them obvious: use a small number of obvious call-to-actions, ensuring clickable areas are no bigger than a fingertip (44×44 pixels).
  • Use a clear, methodical hierarchy and keep it short: create a clear headline followed by secondary messaging, and keep it as brief as possible.
  • Use capitals in titles to distinguish text and content areas.
  • Stick to one or two columns of content: if using more than one column, centre the text in each column to maximise the visual space between them and improve legibility.

The data in Steel’s report came from a nationally representative survey of 500 respondents.