Email subject lines- Does length matter?

Added:Jul 03, 2008

Short email subject lines result in a higher open rate, but longer ones result in more clickthroughs, according to new research.

Analysis of over 600 subject lines and 200 million email messages by email marketing agency Alchemy Worx has disproved the widely held view that short email subject lines are better.

Alchemy Worx discovered that although subject lines with 50 characters or less make more people open the email – the traditional view – they are less likely to then go on and click on content or offers within the message.

The study found that the click-to-open rates start to be optimised when the subject line is over 70 characters in length and continue to rise until well beyond 100 characters.

This is true for both the number of characters and the word count. The more words there were in the subject line, the better the click-to-open rate.

Dela Quist, CEO of Alchemy Worx who commissioned the research, said: “One of the most common questions we’re asked at conferences is what subject lines work best. In the last eight years of working on our clients email marketing programmes we amassed plenty of circumstantial evidence that suggested longer subject lines could be as, if not more effective than shorter ones, so we commissioned this research to find out once and for all.

“In summary our findings show that shorter subject lines optimise open rates, while longer subject lines optimise both click and click-to open rates. We were also surprised to identify a “dead” zone! Subject lines of between 60 and 70 characters (6-10 words), optimise neither the open rate or click to open rates.”

A white paper containing full results and analysis is available at: