Email open rate

Nothing downstream happens if an email is not opened, so open rate has been the standard check on the first step of an email funnel. A steady fall across campaigns can point to a problem with email deliverability or sender reputation, not with the subject line.

Its value today is narrower than it used to be. Because Apple Mail Privacy Protection and some security scanners load emails automatically, the number overstates real reading and no longer tells you who read what. Treat it as a rough direction, for one list over time or one campaign against another, and not as proof of interest.

The decisions worth making rest on what comes after: clicks, replies and bookings. Open rate still helps you spot a sudden drop and compare two subject lines sent to similar segments at the same time.

• Compare against your own past campaigns, not against figures from other businesses.
• Write subject lines around one clear benefit or question, not a vague update.
• Send from a real person's name and address where possible.
• Test one thing at a time, such as subject line or send time, on similar segments.
• Treat a sudden drop as a prompt to check deliverability first.

The formula is opened emails divided by delivered emails, multiplied by 100. Say 1,000 emails are sent and 40 bounce. That leaves 960 delivered. If 288 are opened, the open rate is 30%. Use delivered rather than sent as the base, so that bounces do not distort the number.

An open is recorded when a one-pixel image in the email loads. If the recipient's mail app blocks images, the open is missed. Some apps load the image automatically.

• Treating the number as exact. Since Apple Mail Privacy Protection, many opens are recorded when nobody read anything. Do not report open rate as a result.
• Comparing against other companies' benchmarks. Lists, audiences and tracking differ. Compare with your own past sends.
• Using sent instead of delivered as the base. Bounces then drag the rate down and hide the real picture.
• Optimising for opens at the expense of honesty. A misleading subject line raises opens and then lowers clicks, replies and trust.
• Testing too many things at once, or on tiny lists. Change one element, use similar segments, and send at the same time.
• Stopping at the open. The goal is a reply, a booking or a sale. Track those next to the open rate.

Since Apple introduced Mail Privacy Protection in 2021, Apple Mail can load images for the user in advance, so many opens are recorded when nobody read anything. Open rates are therefore inflated and unreliable as an absolute figure. Use them to compare one campaign with another, and judge success by clicks, replies and bookings.