Beyond Open Rates: The 5 KPIs That Matter in B2B Email Marketing

Let’s start with this bold statement: email marketing is far from dead. In fact, email marketing delivers an average ROI of $42 for every $1 spent. And that’s not just alive, it’s thriving! Email remains one of the most powerful channels for connecting with your audience. 

But here’s the catch: too many marketers are still measuring success using a single, increasingly unreliable metric—the open rate.

That’s a problem. With Apple’s privacy updates skewing open data and Microsoft now rejecting emails from high-volume senders, it’s clear the old way of measuring performance just doesn’t cut it anymore. To truly understand and improve your email marketing, you need to look beyond open rates. 

Why Should I Worry About Email Regulations and Email KPIs?

Apple Mail Privacy Protection (MPP) has made open rates an unreliable metric by preloading email content and masking user behavior. This disrupts how marketers track engagement, especially for those who rely on open rates to measure success. It’s time to adapt.

Meanwhile, new Microsoft requirements demand strict technical compliance to maintain deliverability and accurate KPIs. With open rates already affected by Apple’s MPP, metrics like clicks, replies, and conversions are now more important than ever. Proper authentication, list hygiene, and functional reply addresses are essential to avoid spam folders and protect campaign performance.

Is Email Still Relevant in B2B Marketing?

It’s simple: B2B buyers are asking to be contacted by email! 

According to a 2024 Content Marketing Institute report, 77% of B2B buyers prefer to receive communication via email over any other channel, citing its convenience, clarity, and ability to revisit information when needed. When done well, email respects the buyer’s journey while building trust and delivering value consistently.

What are the Best Email KPIs for B2B Marketing?

1. Click-Through Rate (CTR)

This is the true measure of engagement. It tells you how many recipients were compelled enough by your content or offer to take action.

According to Campaign Monitor, the average email CTR is around 2.3% across industries.

To improve CTR:

• Use clear, action-driven CTAs
• A/B test your button placements and colors
• Personalize your message based on past behavior

Formula: CTR = (Total Clicks / Total Emails Delivered) × 100

2. Conversion Rate

Clicks are great, but what counts is whether those clicks led to a desired outcome: a sale, sign-up, download, or other action.

Marketers who segment campaigns see up to a 760% increase in revenue. Targeted emails convert better, period.

Make sure your landing pages match your email’s message and are optimized for mobile and speed.

Conversion Rate = (Conversions / Total Clicks) × 100

3. List Growth Rate

A healthy email program is one that’s growing. Your list growth rate tracks the net increase of subscribers over time.

Maintaining a clean, growing list ensures better deliverability and long-term success.

List Growth Rate = ((New Subscribers - Unsubscribes - Bounces) / Total Subscribers) × 100

4. Unsubscribe & Spam Complaint Rates

These are the silent killers of your email reputation. A high unsubscribe or complaint rate could signal that your content is irrelevant, too frequent, or worse, unwanted.

A good unsubscribe rate should stay below 0.5%; spam complaints ideally below 0.1%.

Use preference centers, segment wisely, and always offer value to your readers.

Unsubscribe Rate = (Unsubscribes / Total Emails Delivered) × 100

Here’s 5 reasons why your emails are going to SPAM.

5. Lead Quality & Pipeline Contribution

In B2B, it’s not just about immediate revenue but how well your emails contribute to generating qualified leads and moving prospects through the sales pipeline.

Tracking the number of Marketing Qualified Leads (MQLs) or Sales Qualified Leads (SQLs) generated from email campaigns helps measure email effectiveness in driving valuable business outcomes.

Integrate your email platform with your CRM to track lead progression and attribute pipeline growth to your campaigns.

Lead Quality = (Number of MQLs from Email / Total Leads from Email) × 100

Measure What Matters

Open rates are now a fuzzy number at best, and misleading at worst. As inboxes get smarter and users demand more relevance, marketers need to stay agile.

Focusing on metrics like CTR and conversion rate doesn’t just give you better insights — it helps you craft smarter campaigns that drive real business results. 

Let’s keep this conversation going. 

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