Email campaign metrics tell you how your messages are performing — who received them, who engaged, and where the dropoff is. This article explains every major email metric, how it is calculated, what constitutes a healthy benchmark, and what action to take when a metric falls below threshold.
The Email Funnel
Every email campaign moves through a funnel. Understanding where drop-off occurs helps you identify where to focus improvement:
| Stage |
What It Means |
Key Metric |
| 1. Sent |
Total messages dispatched from MigoSMTP |
— |
| 2. Delivered |
Accepted by the recipient's mail server |
Delivery Rate |
| 3. Inbox placement |
Landed in inbox vs spam (not directly measurable via standard delivery) |
Reputation Score |
| 4. Opened |
Recipient viewed the email |
Open Rate |
| 5. Clicked |
Recipient clicked at least one tracked link |
Click Rate, CTOR |
| 6. Converted |
Recipient completed the desired action (purchase, sign-up, etc.) |
Conversion Rate (tracked in your app) |
Metric Definitions and Benchmarks
Delivery Rate
| Formula | (Delivered ÷ Sent) × 100 |
| Healthy target | ≥ 95% |
| Warning | 90–94% |
| Critical | Below 90% — investigate immediately |
| If low | Check bounce rate breakdown; verify domain authentication; review list quality; check if domain or IP is blacklisted |
Bounce Rate
| Formula | (Bounced ÷ Sent) × 100 |
| Hard bounce | Permanent failure — invalid address, domain does not exist. Remove immediately. |
| Soft bounce | Temporary failure — full mailbox, server busy. Retry automatically; remove if persists. |
| Healthy target | Below 2% |
| If high | Clean your list; remove all hard bounces from future sends; validate email addresses at point of collection |
Open Rate
| Formula | (Unique Opens ÷ Delivered) × 100 |
| Healthy target | 20–35% (varies significantly by industry) |
| Important caveat | Apple Mail Privacy Protection (MPP) pre-fetches tracking pixels on iOS 15+, inflating open rates. Treat open rate as a directional indicator rather than an absolute truth since mid-2021. |
| If low | Test different subject lines; send at a better time; segment your list; check if emails are landing in spam |
Click Rate vs Click-to-Open Rate (CTOR)
| Click Rate formula | (Unique Clicks ÷ Delivered) × 100 |
| Click Rate target | 2–5% (overall) |
| CTOR formula | (Unique Clicks ÷ Unique Opens) × 100 |
| CTOR target | 10–20% (measures content quality independently of open rate) |
| If low CTOR | Content is not compelling enough for those who open; review CTA placement, button text, and email value proposition |
Spam Complaint Rate
| Formula | (Complaints ÷ Delivered) × 100 |
| Healthy target | Below 0.1% |
| Warning | 0.1–0.3% — Gmail begins throttling delivery |
| Critical | Above 0.3% — severe deliverability impact; Gmail/Yahoo may block your domain |
| If high | Stop sending immediately; audit your consent practices; clean your list; make unsubscribe more visible and easier |
Unsubscribe Rate
| Formula | (Unsubscribes ÷ Delivered) × 100 |
| Normal range | 0.1–0.5% per campaign |
| If high | Content is not meeting subscriber expectations; review frequency, relevance, and whether you are sending to the right segments |
| Important note | A visible, easy unsubscribe reduces spam complaints. Someone who unsubscribes is better than someone who marks you as spam. |
Reading Metrics in MigoSMTP Delivery Reports
- Log in to MigoSMTP → Reports → Delivery Reports.
- Filter by campaign tag to isolate your campaign's data.
- Select the date range matching your send window (allow 48–72 hours for full data to accumulate).
- Review the summary metrics at the top of the report.
- Click Export to download a CSV with per-recipient delivery status for detailed analysis.
Next Steps