Email & Lifecycle
Email Open Rate Calculator
Open rate is the share of delivered emails that got opened, and since Apple Mail Privacy Protection it is a directional signal rather than a hard number. I still track it, because the trend line tells me when a subject line or a sender reputation is drifting.
Result
FormulaOpen rate = (unique opens ÷ emails delivered) × 100
Worked example
42,000 delivered emails producing 15,540 unique opens is a 37 percent open rate. Pushing that to a 45 percent target on the same list would return 18,900 opens, roughly 3,360 more people reading the message without adding a single subscriber.
What to watch for
Use delivered, not sent. Dividing by sent quietly folds your bounce problem into your engagement number and makes a deliverability issue look like a copy issue.
Apple Mail Privacy Protection pre-fetches images, so a meaningful slice of your opens are machine opens. Treat open rate as a relative trend within your own list rather than an absolute benchmark against someone else's blog post.
Typical opt-in ecommerce and newsletter lists land somewhere in the 25 to 45 percent band post-MPP. If you are below 15 percent on a permission list, look at deliverability and list hygiene before you rewrite subject lines.
Frequently asked questions
Is open rate still worth tracking?
Yes, but as a directional signal, not a KPI. It is inflated by privacy pre-fetching, so a sudden drop is more informative than the absolute level. Use click-through rate and revenue per send when you need a number you can defend.
Why did my open rate fall off a cliff?
In order of likelihood: inbox placement moved to spam or promotions, you mailed a stale segment, your sending domain reputation took a hit, or the tracking pixel is broken. Check deliverability before you touch creative.
Should I resend to non-openers?
Sparingly. A single resend with a different subject line 48 to 72 hours later usually adds real incremental opens. Doing it on every campaign trains the list to ignore you and raises complaint rates.
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