40% open rate. Or is it 20%?Your dashboard says forty percent of people opened your email. Here's the uncomfortable part: it might really be twenty. Open rate is the first number every sender checks, and it's also one of the shakiest. Let's unpack what it actually measures.
⬡ talking-stat, big "Open rate", then two pills fade in: opens ÷ delivered · measured by a tiny pixelOpen rate is simple math. It's the percentage of your delivered emails that registered at least one open. Send a thousand, count the opens, divide. That's it. The tricky word is "registered," because a machine decides when an open counts, not the human reading it.
⬡ talking-stat, formula reveal: opens ÷ delivered = open rateSo how does your ESP know Captain Kraken opened your email? A tiny trick. Almost every marketing email hides a one-by-one transparent image, a tracking pixel. When the email loads that image, it pings a server, and that ping gets logged as an open. No pixel load, no recorded open.
⬡ dissect, an email with a hidden 1x1 pixel highlighted, arrow to "server ping = 1 open"If this is already changing how you read your dashboard, subscribe. We're going through every email metric, one honest number at a time.
⬡ title-card, subscribe line on screenHere's where it wobbles. That pixel can load without a person ever reading anything. In 2021 Apple launched Mail Privacy Protection, and now Apple's servers pre-load images for Apple Mail users automatically, whether or not the human opened it. Gmail routes images through its own proxy too. So a chunk of your "opens" are triggered by machines, not people.
⬡ split-compare, LEFT "real human opens the email" vs RIGHT "Apple's server loads the pixel, nobody read it", both count as +1That's why a forty percent open rate might be twenty real people plus twenty phantom loads. You cannot tell which from the number alone. So treat open rate as a soft, directional signal, not the truth. Absolute numbers lie. Trends on the same list still tell you something.
⬡ gauge-meter, needle labelled "directional, not exact", wobbling rather than locking to a valueOpen rate is opens divided by delivered, counted by a pixel that a machine can trip on its own. Useful for spotting change over time. Not something to quote as gospel.
⬡ title-cardOne habit: watch your open rate move, don't trust its exact height.
Next up: what actually counts as an "open," and every sneaky way that pixel gets tripped. Subscribe and we'll keep going.
⬡ end-card, Subscribe + Next: "What counts as an open" (004.001.002)What is email open rate? It's the percentage of delivered emails that registered at least one open, opens divided by delivered, counted by a tiny 1x1 tracking pixel that pings a server when your email loads images. The catch: since Apple's Mail Privacy Protection launched in 2021, Apple's servers pre-load that pixel for Apple Mail users whether or not anyone read the email, and Gmail proxies images too. So a real chunk of your "opens" are machine-triggered phantoms. Treat open rate as a directional signal, useful for spotting changes over time on the same audience, not as a number you can quote to the decimal. Pair it with click rate and conversion rate for a truer read on engagement.
0:00 The 40% that might be 20%
0:20 The plain definition
0:45 How the pixel measures an open
1:20 Why the number is unreliable (Apple MPP, Gmail proxy)
2:10 What the number really means
Next: What counts as an open → [link 004.001.002]
Full written guide → reviewmyemails.com/emailalmanac/004.001.001
#email #deliverability #openrate