Email Open Rate Calculator

About this calculator

Email open rate is calculated as unique opens divided by delivered emails (not total sent — bounced emails are excluded), expressed as a percentage, and it’s traditionally been the go-to metric for judging how compelling a subject line and sender name are at getting someone to click into an email.

Email marketers should read open rate with some caution today: since Apple’s Mail Privacy Protection launched in 2021, Apple Mail can pre-fetch images and register an “open” automatically for a large share of recipients regardless of whether a human actually looked at the email, inflating reported open rates industry-wide. Even so, marketers still track it as a rough engagement signal and to A/B test subject lines. This calculator divides opens by delivered emails to give you the open rate along with the number of unopened emails.