Key Metrics

Understand essential email marketing metrics to measure success and improve your campaigns

Email Marketing Metrics Overview

Brew tracks important email metrics to help you understand how your campaigns are performing and where you can improve. The basic metrics (sends, opens, clicks) are visible in your email dashboards, while more detailed metrics are available through Brew’s AI-powered analytics.

As shown in the Types of Emails documentation, you can see your basic performance metrics at a glance in the All Emails, Campaigns, Automations, and Transactional pages. Each view displays sends, opens, and clicks for your emails. Other metrics discussed on this page, such as bounce rates, unsubscribe rates, and spam complaints, require using Brew’s AI-powered analytics.

Learn how to use Brew's Analytics

Discover how to analyze your email performance with natural language questions

Core Engagement Metrics

Open Rate

Open rate shows the percentage of delivered emails that were opened by recipients.

Open Rate = (Number of unique opens ÷ Number of emails delivered) × 100

This metric reflects how compelling your subject line and sender name are. It’s your first indicator of audience engagement.

How Open Rates Are Tracked

When you send an email through Brew, here’s exactly how opens are measured:

1. Tracking Pixel Insertion: A 1×1 pixel transparent GIF image is automatically embedded in each email you send. This invisible pixel contains a unique identifier linked to both the specific email and the recipient.
2. Email Delivery: Your email is delivered to the recipient’s inbox with this tracking pixel included.
3. Image Loading: When a recipient opens your email and their email client loads images, it requests this pixel from Brew’s servers.
4. Open Registration: This server request registers as an “open” in Brew’s analytics system, recording who opened the email and when it happened.
5. Data Processing: Brew consolidates this data to calculate your open rate, filtering out duplicate opens from the same user to provide unique open metrics.

Why open rate matters

A higher open rate means more people are seeing your message. It’s the gateway to all other engagement.

Generally, an open rate in the range of 17–28% is considered average to good, with recent industry benchmarks around 21% overall.

Limitations to consider

Several factors can affect open rate accuracy:

• Image blocking: If a recipient’s email client blocks images, opens may not be counted
• Apple Mail Privacy Protection: Automatically loads tracking pixels, which can inflate open rates
• Preview panes: May trigger opens even if emails aren’t actually read

Because of these limitations, open rates should be viewed as directional rather than precise measurements.

When viewing open rate metrics, you can ask Brew for subject line suggestions based on your past performance. For example: “What subject line patterns have led to the highest open rates for my newsletter?”

Click-Through Rate (CTR)

Click-through rate (CTR) is the percentage of delivered emails that resulted in recipients clicking a link within the email.

CTR = (Number of unique clicks ÷ Number of emails delivered) × 100

CTR reflects how engaging and relevant your email content is, and how effective your calls-to-action are at driving action.

How Clicks Are Tracked

Brew tracks clicks through a process called link rewriting:

1. Link Modification: When you create an email, Brew automatically rewrites all links to route through our tracking servers before redirecting to the final destination.
2. Unique Identifiers: Each rewritten link contains parameters that identify both the email campaign and the specific recipient.
3. Click Registration: When a recipient clicks any link, they first connect to Brew’s tracking system, which records the click event along with relevant data (which link, which recipient, timestamp).
4. Instant Redirect: After registering the click, the recipient is immediately redirected to the intended destination URL. This happens so quickly that recipients don’t notice any delay.
5. Reporting: Brew aggregates this click data to calculate metrics like CTR and identifies which specific links received the most engagement.

Why CTR matters

Clicks represent the next level of engagement beyond opens. They indicate that your message was compelling enough for recipients to take action.

Across industries, a 2–5% CTR is common for email campaigns, with around 2.3% being the average.

When reviewing your click rate metrics, ask Brew questions like: “Which types of links get the most clicks in my emails?” or “What content sections drive the most engagement?”

Conversion Rate

Conversion rate measures the percentage of recipients who completed your desired action after receiving your email.

Conversion Rate = (Number of people who completed the desired action ÷ Number of emails delivered) × 100

Why conversion rate matters

Conversion rate is crucial because it measures the business impact of your email campaigns. While opens and clicks are important engagement metrics, conversions represent actual business outcomes.

Tracking conversions

To track conversions, you’ll need to:

1. Define the specific action that constitutes a conversion for each campaign
2. Add UTM parameters to your email links
3. Connect your analytics platform to track these actions

Deliverability Metrics

Bounce Rate

Bounce rate measures the percentage of emails that could not be delivered.

Bounce Rate = (Number of bounced emails ÷ Number of emails sent) × 100

How Bounces Are Tracked

Brew tracks bounces through automated feedback from email servers:

1. Delivery Attempt: When your email is sent, it goes through multiple servers before reaching its destination.
2. Bounce Detection: If a receiving mail server cannot deliver the message, it sends back an automated response (an SMTP error) with a specific reason code.
3. Classification: Brew’s system automatically categorizes these bounce responses into hard bounces (permanent failures) or soft bounces (temporary issues) based on the error codes and message.
4. Recording: The bounce is logged in your campaign metrics along with the specific reason for the failure.
5. Automated Handling: For hard bounces, Brew automatically suppresses the email address to prevent future sending attempts, protecting your sender reputation.

There are two important types of bounces:

Hard Bounces

Permanent failures due to invalid addresses or blocked domains

Soft Bounces

Temporary issues like full mailboxes or server problems

Keep your bounce rate under 2%. If your hard bounce rate exceeds 3%, Brew may temporarily pause sending to protect your domain reputation.

Spam Complaint Rate

The spam complaint rate is the percentage of delivered emails that recipients marked as “Spam” or “Junk”.

Spam Complaint Rate = (Number of spam complaints ÷ Number of emails delivered) × 100

How Spam Complaints Are Tracked

Spam complaints are tracked through a standardized system called Feedback Loops (FBLs):

1. Recipient Action: A recipient clicks the “Mark as Spam” or “Report Spam” button in their email client.
2. ESP Notification: The receiving email service provider (like Gmail, Yahoo, or Outlook) captures this action and sends a standardized report through a Feedback Loop.
3. Complaint Processing: Brew receives these FBL reports and associates them with the specific email campaign and recipient.
4. Automatic Suppression: The complainant’s email address is automatically added to a suppression list to prevent any future emails from being sent to them.
5. Metric Calculation: Brew aggregates these complaints to calculate your spam complaint rate and provides alerts if rates approach concerning thresholds.

Aim to keep your spam complaint rate below 0.1%. If it exceeds 0.2%, Brew may temporarily suspend sending to protect your sender reputation.

Unsubscribe Rate

Unsubscribe rate measures the percentage of recipients who opted out of future emails.

Unsubscribe Rate = (Number of unsubscribes ÷ Number of emails delivered) × 100

How Unsubscribes Are Tracked

Brew tracks unsubscribes through an intuitive preference management system:

1. Unsubscribe Link: Every email sent through Brew includes a legally-required unsubscribe link, typically in the footer. This link contains a unique identifier for the recipient.

2. Preference Center: When a recipient clicks this link, they’re taken to your branded Preference Center rather than being immediately unsubscribed. Here they can see all your subscription groups with descriptions.

3. Granular Control: Instead of a single “unsubscribe from everything” option, recipients can use toggle switches to choose which specific content types they want to continue receiving. This reduces total unsubscribes by letting contacts opt out of only the content they don’t want.

4. Immediate Processing: When a recipient updates their preferences, Brew instantly records these changes and updates their status in your audience.

5. List Suppression: The system automatically ensures this contact will no longer receive emails from the unsubscribed groups, while still allowing them to receive content from groups they remain subscribed to.

Most email experts consider an unsubscribe rate below 0.5% to be normal.

Learn about the Preference Center

Customize how subscribers manage their email preferences with your branding

Learn about Subscription Groups

Create content categories that give subscribers more control over what they receive

Advanced Metrics Analysis

While basic metrics are visible in your email dashboards, more complex analysis can be performed using Brew’s AI analytics features:

Ask Brew button

Located at the bottom of your email dashboards, this feature allows you to ask specific questions about email performance:

“Why did this email perform better than my previous one?”

“What was the bounce rate for my last campaign?”

“How many people unsubscribed from my newsletter series?”

“What caused the drop in clicks between emails 2 and 3 in this automation?”

Analyze tab

Access this from the main navigation menu to explore broader patterns and trends:

“Show me a graph of my open rates over the last quarter”

“Which day of the week gets the best engagement?”

“Compare unsubscribe rates between my welcome sequence and newsletter”

“What’s my average spam complaint rate across all campaigns?”

For comprehensive guidance on using these features, see our Analytics documentation.

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