Should you capitalize your subject lines?
As any other SDR Leader, I am not just sending outreach emails, but also receiving plenty of them from other salespeople. Recently, I’ve started noticing an interesting trend with many subject lines containing only lower case words, e.g., “sales development consulting for reply.io” or “reply.io lead generation services.”
Since it did catch my attention (and people seemed to be doing it on purpose), I got curious: Could the letter case used in your subject line really influence the open rate?
To find that out, we analyzed 3 variants of the same subject line containing:
- all lower case words → sales development process at reply.io
- most lower case words → Sales development process at Reply.io
- most upper case words → Sales Development process at Reply.io
Long story short, it could indeed influence the open rate, yet correlation isn’t that significant, according to the research 👇:
- The subject line containing all lower case words (variant #1) generated 3.46% fewer opens. The average reply rate here was lower by 11%.
- Using the subject line with mostly lower case words (variant #2) didn’t affect our open and reply rates, keeping them close to the average (just some 0.22% higher).
- For the subject line containing most upper case words (variant #3), the open rate was 2.46% higher and reply rate — 10.93% higher. This means we have the winner!
As you can see, every little nuance can make a real difference when it comes to cold outreach.
💡 So, if you’re looking to increase your open and reply rates, here’s a trick: Instead of coming up with the new subject lines, try capitalizing most words within the existing one and see what happens!