Most SaaS companies track the wrong email metrics. Open rates and click rates are fine, but they don't tell you if email is actually driving revenue. Here are the KPIs that matter and how to move them.

Why Traditional Email Metrics Fall Short for SaaS

The metrics you'll find in any email marketing 101 guide—open rates, click rates, unsubscribe rates—were designed for newsletters and e-commerce. They measure engagement with emails, not impact on your business.

For SaaS, email success should connect directly to product metrics:

Did trial users activate?
Did they convert to paid?
Did churning users come back?
Did existing users upgrade?

If your emails have great open rates but don't move these numbers, you're optimizing for the wrong thing.

The SaaS Email Metrics Stack

Tier 1: Revenue Impact Metrics

These are your north star metrics—the ones that directly connect to revenue.

Trial-to-Paid Conversion Rate by Email Engagement

What it measures: Do users who engage with onboarding emails convert at higher rates than those who don't?

How to calculate: Conversion rate of users who clicked an onboarding email vs. those who didn't.

Benchmark: Email-engaged users should convert 20-50% better than non-engaged users. If there's no difference, your emails aren't adding value. For specific sequence guidance, see our detailed guide on trial-to-paid conversion strategies.

How to improve it:

Make email CTAs lead to activation actions, not just "learn more" pages
Time emails based on user behavior, not arbitrary schedules
Test different value propositions in your messaging

Email-Attributed Revenue

What it measures: How much revenue can you trace back to email campaigns?

How to calculate: Sum of MRR from users who converted after clicking an email in their attribution window (typically 7-30 days).

Benchmark: Varies widely, but email should be one of your top 3 conversion channels for most SaaS.

How to improve it:

Implement proper UTM tracking on all email links
Connect your email platform to your revenue data (Stripe, billing system)
Build upgrade prompts based on usage patterns

Expansion Revenue from Email

What it measures: MRR increase from existing customers who upgraded after email campaigns.

Why it matters: Expansion is often more valuable than new acquisition. Email is one of the best channels to drive it.

How to improve it:

Segment by usage—target users approaching limits
Show specific features they'd unlock by upgrading
Time prompts to moments of high engagement

Tier 2: Activation Metrics

These metrics connect email to product activation—the behaviors that predict conversion.

Activation Rate by Email Cohort

What it measures: What percentage of users who received/engaged with specific emails completed your activation milestone?

How to calculate: Users who activated / Users who received the email sequence

Benchmark: Depends on your activation definition. The key is comparing cohorts—email recipients vs. control groups.

How to improve it:

Map your activation milestone clearly (what specific action predicts conversion?)
Design emails that reduce friction to that action
Send activation-focused emails within the first 24-48 hours

Time-to-Activation

What it measures: How quickly do users reach activation after signup?

Why it matters: Faster activation correlates with higher conversion and retention.

How to improve with email:

Send the first onboarding email immediately (not next morning)
Include one clear action in each email
Remove distractions—don't send feature tours to users who haven't activated

Feature Adoption Rate

What it measures: Did users who received feature announcement emails actually try the feature?

How to calculate: Users who tried feature / Users who received the email

How to improve it:

Segment by relevance—only announce features to users who'd benefit
Show the feature in context of their specific use case
Include a direct link to try the feature, not just a blog post

Tier 3: Engagement Metrics

These are your leading indicators—they predict Tier 1 and 2 outcomes.

Deliverability Rate

What it measures: What percentage of emails successfully reach recipients' servers?

Benchmark: Should be 97%+ for a healthy list. Learn more about email deliverability fundamentals and the factors that impact your inbox placement.

Warning signs:

Below 95%: Something is wrong—investigate immediately
Sudden drops: Check for authentication issues or blacklisting
High soft bounces: Might indicate reputation problems

Open Rate

What it measures: Percentage of delivered emails that were opened.

SaaS Benchmark: 20-40% for marketing emails, 60-80% for transactional.

Important caveat: Apple Mail Privacy Protection makes open tracking unreliable. Use open rates for trends, not absolute numbers.

How to improve:

Test subject lines (questions vs. statements, personalized vs. generic)
Optimize send times for your audience
Build sender reputation over time

Click Rate

What it measures: Percentage of delivered emails where a link was clicked.

SaaS Benchmark: 2-5% for marketing, higher for targeted behavioral emails.

How to improve:

One CTA per email—don't make users choose
Make the CTA specific ("Start your first project" vs. "Learn more")
Place the primary CTA above the fold

Reply Rate

What it measures: How many recipients replied to your email?

Why it matters for SaaS: Replies indicate engagement and can provide valuable feedback. Plus, replies improve deliverability.

How to improve:

Ask specific questions
Send from a real person, not a no-reply address
Make emails conversational

Tier 4: Health Metrics

These protect your email program from self-destruction.

Spam Complaint Rate

What it measures: Percentage of recipients who clicked "Report Spam."

Benchmark: Must stay below 0.1% (1 complaint per 1,000 emails). Gmail and Yahoo will throttle you above 0.3%.

How to maintain:

Only email people who opted in
Make unsubscribe easy and visible
Set expectations at signup about email frequency

Unsubscribe Rate

What it measures: Percentage who unsubscribed from an email.

Benchmark: Under 0.5% per campaign is healthy. Consistent 1%+ indicates a problem.

Note: Some unsubscribes are healthy—better than spam complaints.

List Growth Rate

What it measures: Net growth of your email list after accounting for unsubscribes and bounces.

How to calculate: (New subscribers - Unsubscribes - Bounces) / Total subscribers

Why it matters: A shrinking list eventually kills email as a channel.

Building Your SaaS Email Dashboard

Don't track everything—focus on what drives decisions. Here's a recommended dashboard:

Weekly Review

Email-attributed trial conversions
Activation rate by email cohort
Deliverability rate
Spam complaint rate

Monthly Review

Email-attributed revenue (new + expansion)
Sequence performance (conversion rate by sequence)
List growth rate
Engagement trends over time

Quarterly Review

Email ROI (revenue attributed / cost of email program)
Comparison of email vs. other channels
Cohort analysis (do users who engaged with email have better LTV?)

Common Measurement Mistakes

Mistake 1: Optimizing Open Rates in Isolation

You can boost open rates with clickbait subject lines, but if those opens don't convert, you're wasting time and potentially training users to distrust your emails.

Better approach: Optimize for click-to-conversion, not just opens.

Mistake 2: Treating All Emails the Same

A 20% open rate means different things for a newsletter vs. a trial-ending warning. Set benchmarks by email type:

Transactional: 60-80% open rate expected
Onboarding: 40-60% open rate expected
Marketing newsletters: 20-35% open rate expected
Re-engagement: 10-20% open rate expected

Mistake 3: Ignoring Unsubscribes

A 0% unsubscribe rate isn't healthy—it probably means your list has dead addresses. Some unsubscription is natural and healthy. Focus on whether unsubscribers were people you wanted to keep.

Mistake 4: Not Connecting to Revenue

If you can't answer "how much revenue did email drive this month?" you're missing the most important metric. Set up attribution, even if imperfect, so you can make the case for email investment. Understanding conversion rates and how to attribute them to email is critical for this.

The Bottom Line

The best SaaS email teams focus on metrics that predict revenue:

Revenue impact — Trial conversion, email-attributed revenue, expansion revenue
Activation — Activation rate by cohort, time-to-activation, feature adoption
Engagement — Deliverability, opens, clicks (as leading indicators)
Health — Spam complaints, unsubscribes (to stay out of trouble)

Start with the basics—deliverability and complaints. Then build toward connecting email to your core product and revenue metrics. The companies that do this well treat email as a product feature, not just a marketing channel.