Key takeaways
- Since Apple Mail Privacy Protection (2021), open rates are inflated and unreliable for judging subject lines or engagement.
- Judge campaigns by click rate, conversion rate and revenue per email.
- Guard list health with bounce rate (under 2%), spam-complaint rate (under 0.1%) and unsubscribe rate.
- Compare against your own baseline and segment by provider — industry averages hide more than they reveal.
Email platforms report dozens of numbers after every send. Some tell you whether your emails make money; some tell you whether your list is healthy; and one of the most famous — open rate — hasn't meant what most people think it means since 2021.
Here's what to track, how to calculate it, and what to do when a number moves the wrong way.
Why open rates stopped telling the truth
Opens are measured with a tiny invisible image: when it loads, the email counts as opened. In September 2021, Apple released Mail Privacy Protection (MPP) with iOS 15. For users who turn it on, Apple Mail preloads images through its own proxy servers — whether or not the person ever looks at the email.
The result: emails sent to Apple Mail users can register as "opened" even when nobody read them. Since Apple Mail accounts for a large share of opens on many lists, reported open rates rose sharply overnight. Other effects to be aware of:
- Opens are recorded at odd times, often shortly after sending, regardless of when the person reads.
- Location data from opens reflects Apple's proxy servers, not the reader.
- Subject-line A/B tests judged on opens can pick the wrong winner.
- Workflows that branch on "opened" may send the wrong follow-up.
- Conversely, clients that block images under-count real opens.
Treat opens as a rough health signal, not a success metric. Clicks and conversions are actions a machine can't fake as easily.
Performance metrics: is email making money?
| Metric | Formula | What it tells you |
|---|---|---|
| Click-through rate (CTR) | Unique clicks ÷ delivered × 100 | How compelling the content and offer were |
| Conversion rate | Conversions ÷ delivered × 100 | How many recipients did what you wanted — bought, booked, registered |
| Revenue per email (RPE) | Revenue ÷ delivered | Compares campaigns of different sizes on one scale |
| Revenue per subscriber | Email revenue in a period ÷ average list size | The value of adding one more subscriber |
| Return on investment (ROI) | (Revenue − cost) ÷ cost × 100 | Whether the programme pays for itself |
Revenue per email is the single most useful number for comparing campaigns: a small segmented send that earns more per email is beating a big blast, even if its total revenue is lower.
To measure conversions accurately, add UTM parameters to every link (utm_source=email&utm_medium=email&utm_campaign=…) and set up goal tracking so purchases are attributed to the campaign that drove them.
List health metrics: is your audience still reachable?
| Metric | Formula | Healthy range |
|---|---|---|
| Hard bounce rate | Hard bounces ÷ sent × 100 | Under 2% (ideally under 0.5%) |
| Spam complaint rate | Complaints ÷ delivered × 100 | Under 0.1%; never near 0.3% |
| Unsubscribe rate | Unsubscribes ÷ delivered × 100 | Stable over time; watch for spikes |
| List growth rate | (New − unsubscribes − bounces − complaints) ÷ list size × 100 | Positive, month after month |
| Delivery rate | Delivered ÷ sent × 100 | Above 98% |
These numbers feed directly into sender reputation. A campaign with a high complaint rate doesn't just underperform — it makes your next campaign more likely to land in spam. Our deliverability guide explains how reputation is built and repaired.
Engagement: who is actually paying attention?
Campaign-level averages hide individual behaviour. Look at subscribers too:
- Engaged segment size — how many contacts clicked in the last 30, 90 and 180 days. This is your real audience.
- Engagement scoring — points for clicks, purchases and replies, decaying over time, so you can target your best fans and spot fading ones.
- Time to first click — how quickly engaged readers act, which helps you choose send times.
- Click maps — which links and positions earn clicks, so you can improve layout.
When the engaged segment shrinks while the total list grows, you're adding the wrong subscribers or sending the wrong content — and a re-engagement workflow is overdue.
How to use benchmarks without being misled
Industry benchmark reports are a starting point at best. They mix different list sizes, audiences, email types and — since 2021 — very different levels of Apple Mail usage. A better approach:
- Set your own baseline: the median of each metric over your last 10–20 comparable campaigns.
- Compare like with like: newsletters with newsletters, automated flows with automated flows.
- Break results down by mailbox provider: a drop that only happens at Gmail or Outlook points to a deliverability issue, not a content one.
- Watch trends, not single sends: one bad campaign is noise; three in a row is a signal.
When a metric drops: what to check
| Symptom | Likely cause | First thing to try |
|---|---|---|
| Clicks fall across all providers | Content or offer less relevant | Segment more tightly; test a clearer call-to-action |
| Opens and clicks fall at one provider | Filtering to spam there | Check authentication and Postmaster data; mail only engaged contacts for a while |
| Bounces spike | Old or imported addresses | Verify the list; remove hard bounces |
| Complaints spike | Unexpected content or frequency | Review consent source; make unsubscribing easier; reduce frequency |
| Unsubscribes spike | Frequency jump or off-topic send | Offer a preference centre with "fewer emails" |
A simple monthly email dashboard
You don't need fifty charts. Review these each month and you'll catch almost every problem early:
- Total email revenue and revenue per email
- Median click rate for campaigns and for each automated workflow
- Conversion rate on your main goal
- Hard bounce and spam-complaint rates
- Net list growth and engaged-segment size
- Results by mailbox provider
Lebx Mail's real-time reports include open and click maps by country and device, side-by-side comparison reports, engagement scoring and exports, so this dashboard takes minutes rather than an afternoon in spreadsheets.
Frequently asked questions
What is a good email click-through rate?
It varies widely by industry, list and email type — automated emails typically earn much higher click rates than broadcast newsletters. The most useful benchmark is your own: track your median click rate over the last few months and aim to beat it.
Should I still track open rates?
Yes, but carefully. Opens are still useful for spotting big deliverability problems — for example, a sudden drop at one provider — and as a rough relative signal. They are no longer reliable for A/B testing subject lines or judging individual engagement, because Apple Mail Privacy Protection records many automatic "opens".
What is the difference between CTR and CTOR?
Click-through rate (CTR) is unique clickers divided by delivered emails. Click-to-open rate (CTOR) is unique clickers divided by unique opens. Because opens are inflated by privacy protection, CTOR is now much less reliable than CTR.
What spam complaint rate is acceptable?
Keep it below 0.1%. Google and Yahoo require bulk senders to stay under 0.3%, and rates approaching that level will hurt inbox placement well before you hit the limit.