Open rate

Open rate is the ratio of opened emails to delivered ones. It's driven most by the subject line, sender name and send time.

Why it matters

Without an open, nothing else happens. Open rate is email's first gate — even the best offer is useless if no one opens the message.

Real-world example

An A/B test of two subject lines shows a concrete benefit, "Save 20% by Sunday", lifts open rate from 22% to 34% versus a generic "Newsletter".