What is email open rate?
Email open rate is the share of delivered emails that were opened. It has long been the headline email metric, the first read on whether a subject line and sender earned attention. It is also the least reliable email metric today. Tracking opens depends on loading a hidden pixel, and privacy features now load that pixel automatically, whether or not anyone read the message.
The open rate formula.
Open rate = (unique opens divided by delivered) times 100. Delivered is what you sent minus what bounced, so bounces do not count against the rate. Use unique opens, not total opens, so one person opening five times counts once. Total opens measure interest, not reach.
A worked example.
You deliver 2,000 emails and 400 are opened. Open rate is 400 divided by 2,000, times 100, which is 20%.
What is a good open rate?
Typical open rates fall in a wide band, often 20 to 40% depending on industry and list quality, but the number is now inflated by Apple Mail Privacy Protection, which auto-opens messages for a large share of users. Treat any open rate as directional. The honest comparison is your own trend, and click-based metrics carry more signal.
How to improve it.
Write subject lines that set an honest expectation, send from a recognizable name, and keep your list engaged so messages reach the inbox. Sender reputation drives whether you are seen at all. Deliverability and reach also depend on list quality, which starts with attracting the right subscribers.