5 Email Metrics Klaviyo Doesn't Calculate — And Why They Matter
Klaviyo is great, we use it for every client. But there are metrics it doesn't give you out of the box—metrics that actually change how you run your email program.
So we built them ourselves.
Here are five metrics we calculate that Klaviyo won't show you (easily, at least), why they matter, and how to get them.
1. Time to First Purchase
What it is: The number of days between when someone joins your list and when they make their first purchase.
Why Klaviyo doesn't show it: Klaviyo tracks flow performance and campaign performance, but it doesn't connect signup date to first purchase date in a way you can easily report on.
Why it matters: This tells you how long your welcome sequence actually needs to be. If most people convert within 3 days, a 14-day welcome flow is wasted effort after day 3. If people take 30 days, you need more touches.
It also benchmarks your welcome flow performance. If your time to first purchase is 15 days and you make changes that drop it to 10 days, you've measurably improved. Use our LTV Calculator to see how faster conversions impact customer lifetime value.
How to calculate it:
- Export profiles with signup date
- Export orders with customer email and order date
- Match first order to profile
- Calculate days between signup and first order
- Average it (and look at distribution, not just average)
2. Time to Second Purchase
What it is: The number of days between a customer's first and second purchase.
Why Klaviyo doesn't show it: Same issue—Klaviyo doesn't natively connect order sequences per customer in a reportable way.
Why it matters: This is your repeat purchase window. It tells you:
- When to send post-purchase flows pushing the second order
- How long someone is "warm" after their first purchase
- Whether your retention efforts are working
If time to second purchase is 45 days, hitting them with "buy again" emails on day 7 is too early. Hitting them on day 60 is too late. Use our Churn Calculator to understand your drop-off points.
How to calculate it:
- Export orders by customer
- Identify first and second order per customer
- Calculate days between
- Average (and segment by product or acquisition source for more insight)
3. Average Days Between Purchases
What it is: The average gap between any two consecutive purchases for repeat customers.
Why it matters: This is your natural purchase rhythm. It tells you:
- When replenishment flows should trigger
- How often to email your best customers without annoying them
- Whether customers are speeding up or slowing down over time
If your average is 30 days, you should be sending "time to reorder" emails around day 25. If it's 90 days, your cadence needs to adjust.
How to calculate it:
- Export all orders by customer
- For customers with 2+ orders, calculate days between each consecutive pair
- Average across all gaps
4. Average Email Frequency Per Subscriber
What it is: The average number of emails each subscriber receives over a given period.
Why Klaviyo doesn't show it: To get this, you have to run a custom frequency report grouped by emails received per address. Then export it to a spreadsheet and calculate the average yourself. There's no dashboard that just shows you "your average subscriber gets X emails per month."
Why it matters: This tells you whether you're over-emailing or under-emailing your list. If your average subscriber gets 2 emails a month, you're probably leaving money on the table. If they're getting 25, you might be burning them out.
It also helps you spot distribution problems. Maybe your average is 8 emails/month, but some people are getting 20 while others get 2. That's a segmentation issue.
How to calculate it:
- Run a frequency report in Klaviyo (Custom Reports → Frequency)
- Group by emails received per address
- Export to a spreadsheet
- Calculate the average (and look at the distribution—min, max, median)
5. Flow Revenue by Month, Per Flow
What it is: How much revenue each flow generates, broken down by month.
Why Klaviyo doesn't show it: Klaviyo shows total flow revenue, and you can filter by date range, but you can't easily see a trended view of each flow's performance over time in one place.
Why it matters: This tells you things like:
- Is your welcome flow getting better or worse?
- Did that change you made to the abandoned cart flow actually improve revenue?
- Are any flows declining that need attention?
- Did something go wrong that you didn't see—like a website update that killed a metric—that's tanking a flow?
Without this, you're flying blind. A flow could be slowly dying and you wouldn't notice until it's way down. Our Flow Visualizer can help you see your entire flow architecture at a glance.
How to calculate it:
- Export flow performance data by date
- Group revenue by flow and by month
- Build a simple dashboard or spreadsheet that shows the trend
Why This Matters
These aren't vanity metrics. They change how you operate:
- Time to first purchase → Optimize welcome flow length and timing
- Time to second purchase → Time your post-purchase and retention flows
- Days between purchases → Set replenishment flow triggers
- Email frequency per subscriber → Spot over/under-emailing and distribution issues
- Flow revenue by month → Catch declining flows before they crater
Klaviyo gives you a lot. But if you're not calculating these yourself, you're missing the metrics that actually drive decisions. These metrics also inform how you should segment by purchase behavior instead of engagement.
We built these into our internal portal so we can see them for every client. If you want help setting up similar tracking, reach out.