Monitoring Email Metrics for ROI Insights

If my campaign hit a 35% open rate, I’d do a little dance and call it a win.

But here’s the kicker… none of those opens ever guaranteed I was actually making money.

And I didn’t realize that until I had one launch that flopped hard. I sent six beautifully designed emails, complete with GIFs, countdown timers, the whole nine yards. People clicked, they browsed, and then… crickets. Barely any sales came in. I stared at my Mailchimp dashboard thinking, “Well, this felt successful, so what happened?”

That’s when I realized I was measuring the wrong things. It’s not about what feels good — it’s about what converts.

The Wake-Up Call: Clicks ≠ Cash

If you’re not tracking the right email metrics, you’re basically playing darts in the dark. And let me tell you, I’ve hit the wall (and missed the board entirely) more times than I care to admit.

Once I started digging into ROI-specific email metrics, things got real. I started using UTM parameters to track my campaigns in Google Analytics, connected my email platform to Shopify, and ran reports on how much revenue each campaign actually pulled in. And guess what? Some of my lowest open rate emails brought in the most money.

Why? Because the right people got the right message — and they bought. Simple as that.

What I Track Now (and You Should Too)?

Here’s the short list of metrics I monitor religiously now — not just because they look good in a report, but because they tell me what’s actually working:

• Revenue per Email (RPE): This changed the game for me. I take the total revenue generated from a campaign and divide it by the number of emails sent. If it’s under $0.30, I usually go back and reevaluate the offer or list segment.

• Conversion Rate: Forget open rates. I want to know how many people clicked and then bought something. That’s the real story.

• Subscriber Lifetime Value (LTV): I started estimating this with help from Klaviyo, and it really shifted how I think about nurturing my list. Some subscribers are worth $10 over time, others $100+. Knowing the difference helps me prioritize.

• Unsubscribe Rates: If I see a spike, I ask myself: was the content irrelevant, or did I send too many emails too fast?

You don’t need to obsess over every metric, but if you’re not tying your emails back to real dollars, you’re just guessing. And that’s expensive.

Tools That Actually Help (Not Just Look Fancy)

Okay, quick confession: I’ve tried just about every email platform out there. Some of them promise beautiful templates but give you zero data on how your emails perform. That’s a hard pass for me now.

Here’s what I actually use and recommend:

• Klaviyo: If you’re on Shopify or WooCommerce, Klaviyo is a no-brainer. It gives you revenue breakdowns by email, flow, and even individual customer behavior.

• ConvertKit: I love this one for selling digital products. It’s lightweight but powerful, and lets me track purchases and subscriber growth easily.

• Google Analytics + UTM Tags: This takes a bit of setup, but once you get it going? Total game changer. I can see exactly which emails led to sales, how long someone took to buy, and where they bounced.

One time I discovered that a seemingly “low-performing” newsletter was bringing in 3x more revenue than my flashy sales emails — all because GA showed the deeper story.

What I Wish I Knew Sooner?

If I could go back and tell past-me one thing, it’d be: track everything like you’re building a case in court. You need evidence. Without it, you’re just throwing spaghetti at the wall and hoping it sticks.

Also? Not all unsubscribes are bad. Some people just aren’t your audience. Focus on nurturing the folks who do engage and buy. Their behavior will show you what works.

And lastly — don’t get too hung up on benchmarks. I used to freak out if I didn’t hit industry averages. But you know what matters more? Improvement. If your RPE goes from $0.10 to $0.40, you’re doing something right. Celebrate that.

Final Thoughts

Look, email marketing is still one of the highest ROI channels out there — but only if you stop chasing vanity metrics and start tracking what moves the needle. I learned this the hard way, and I’m still learning every time I hit “Send.”

So set up those UTM tags. Connect your platforms. Look past the opens and start tracking revenue per campaign. You’ll be shocked at what’s working (and what’s not).

And hey, don’t be afraid to prune your list or experiment with messaging. Data doesn’t lie. Just make sure you’re actually collecting the right data.

Because at the end of the day, email success isn’t about looking good — it’s about making money.