Email Marketing Metrics: How to Measure What Actually Matters
The email metrics that matter for UK businesses — deliverability, open and click rates, and the conversion metrics that tie email to revenue.
Email produces reams of numbers, but only a handful matter. This guide explains the metrics that actually help you decide what works — and how to read them honestly instead of chasing vanity numbers.
Start with the metric tied to your goal
The metric you optimise for should depend on your primary goal: an ecommerce store cares about revenue per send, a B2B team about replies and meetings booked, a content business about engagement and clicks through to the site. Pick your primary metric first, then use the others to diagnose.
Delivery and open metrics
| Metric | What it measures | Why it matters |
|---|---|---|
| Delivered rate | Messages that reached inboxes | Low delivery hides every other problem |
| Open rate | Delivered emails actually opened | A proxy for subject line and list interest |
| Click rate | Opened emails that got a click | Measures relevance and call to action |
| Bounce rate | Emails that were rejected | High bounces signal list hygiene problems |
| Unsubscribe rate | People who left the list | A tool for spotting over-sending |
| Spam complaint rate | People who reported you | Too high and providers throttle you |
Why open rate isn't the whole story
Open rate relies on pixels that are often blocked, so treat it as a guide rather than a truth. Modern email clients increasingly prevent tracking. Click and conversion metrics are more reliable signals that people actually engaged.
Conversion and revenue metrics
For ecommerce, the numbers that pay the bills are: revenue per email, conversion rate from email, average order value, and return on spend. For B2B, the equivalents are replies, booked meetings, qualified leads, and pipeline influenced.
Metrics that tie email to money
- Revenue per send (total email revenue ÷ sends)
- Order conversion rate from email clicks
- Attributed revenue from automated messages (welcome, cart, win-back)
- Cost per acquisition from email vs other channels
How to benchmark
Any figure you read online — including here — is an average, not a target. Your own trends over time are the benchmark that matters. Compare this month against last month and last year, not against a stranger's list of a different size and industry.
A simple monthly review
Walk through this each month
- Check delivered rate: is email reaching inboxes?
- Pick your three best and three worst senders by click rate.
- Ask why the top ones worked and whether you can repeat them.
- Confirm your primary metric moved in the right direction.
- Kill or fix whatever is dragging your list down.
Tip
Keep a simple spreadsheet. After three months of consistent tracking you'll know your own healthy ranges better than any industry average.
Learn the fundamentals of email marketing and measurement.
Frequently asked questions
What is a good open rate?
There's no reliable universal number. Use your own trends and Google's published averages by industry as a rough reference, not a target.
Is open rate still accurate?
Less so than before, because tracking pixels are often blocked or limited. Prefer clicks, replies and conversions.
What metric should I track first?
One tied to your goal — usually conversions or revenue for businesses, delivered rate too if deliverability is a concern.