Open rate: what it measures now, and what it can't
The share of people who opened your email. Useful for a long time, and a lot less honest since Apple started opening mail on its users' behalf.
- 094Open Rate
- The percentage of recipients who opened your email, indicating the effectiveness of your subject line and sender name.
- Measured as
- Unique opens divided by emails delivered
- Where you see it
- Every campaign and flow report in Klaviyo
- Still good for
- Spotting a deliverability problem early
- Don't use it for
- Picking a subject line winner on its own
An open is a picture loading, not a person reading
Every marketing email carries a tiny invisible image. When it loads, the platform counts an open. That's the whole mechanism, and it's why open rate was always an estimate: plenty of people read with images switched off, and they never counted.
Since Apple added Mail Privacy Protection, the estimate runs the other way. Apple Mail can fetch those images in the background, whether or not anyone looks at the email, so a chunk of your opens are machines. Apple explains the feature in its own Mail privacy documentation.
How the open rate number is worked out
Take the people who opened at least once, divide by the emails that were actually delivered, and multiply by a hundred. Bounces come out of the bottom of the sum, which is why a list full of dead addresses can flatter you here and hurt you everywhere else.
- Unique opens, not total opens: one reader opening five times still counts once
- Delivered, not sent: anything that bounced isn't in the denominator
- Machine opens are in there unless your platform strips them out
Klaviyo tags the opens it thinks Apple's privacy feature generated, so you can look at the number with them taken out. Do that before you compare anything.
What to steer by now that opens are inflated
Open rate still earns its place as a smoke alarm. A sudden drop at one mailbox provider usually means you've started landing in spam there, and that's worth knowing within the week. Just don't crown a subject line on opens alone.
| Question | Better number |
|---|---|
| Did the subject line work? | Clicks and placed orders per recipient |
| Is this person still engaged? | A click or a site visit in recent months |
| Are we reaching the inbox? | Opens by mailbox provider, watched over time |
If your open rate looks too good to be true, it probably is. We've written up why your open rate looks so high and what's usually behind it.
Related terms
FAQs
What is a good open rate for ecommerce emails?
Honestly? The one you had last quarter, measured the same way. Since Apple started opening mail for its users, published averages mix machine opens with real ones, so a benchmark tells you more about your list's iPhone share than about your emails. Compare yourself to yourself, with Apple's opens filtered out.
Why did our open rate jump overnight?
Usually because more of your list moved to Apple Mail with privacy protection switched on, or because a list import added people who auto-open. It's rarely the subject lines. Check the opens split by email client before you celebrate, and check clicks, which didn't move.
Should we stop tracking open rate altogether?
No. Keep it as a warning light. A sharp fall at one inbox provider is still one of the quickest signs of a deliverability problem. Just stop using it to judge creative or to define who's engaged, because clicks and orders do both jobs better.
Rather we explained it on your own account?
Bring your Klaviyo account to a growth consultation. We'll walk through what this means for your numbers, in plain English, and what we'd fix first.
Half an hour with Theo, our founder.
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