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Metrics & Analytics

List Growth Rate

The rate at which your email list is growing, accounting for new subscribers minus unsubscribes and bounces.

Definition

List growth rate measures how quickly your email list is growing (or shrinking), accounting for new subscribers gained and subscribers lost through unsubscribes, bounces, and cleaning. Calculated as ((new subscribers - lost subscribers) / total subscribers) × 100, it indicates the overall health and trajectory of your email program.

Why It Matters

Positive list growth indicates a healthy, expanding audience. Negative growth (more losses than gains) signals problems - poor acquisition, content issues, or delivery problems. Monitoring growth rate helps you catch trends before they become critical and ensure long-term program sustainability.

How It Works

Track three numbers over a period (weekly, monthly, quarterly): new subscribers added, subscribers who unsubscribed or bounced, and total list size. The formula: (new - lost) / total × 100. A 2% monthly growth rate doubles your list in about 3 years; negative growth erodes it.

Example

Monthly list growth calculation:

Starting list: 10,000 subscribers New subscribers: 500 Unsubscribes: 150 Hard bounces: 50 Cleaned (inactive): 100

Net growth: 500 - 150 - 50 - 100 = 200 Growth rate: (200 / 10,000) × 100 = 2%

End of month list: 10,200 subscribers

Best Practices

  • 1Track net growth, not just new subscribers
  • 2Aim for positive growth each period
  • 3Investigate unusual spikes in unsubscribes or bounces
  • 4Balance acquisition efforts with retention
  • 5Clean your list regularly even though it reduces total count

Frequently Asked Questions

Typical healthy growth is 2-5% per month for established lists. New lists may grow faster. Negative growth is concerning and requires investigation. Very high growth rates should be verified for quality, not just quantity.

No - cleaning improves list quality even if it reduces size. A smaller, engaged list outperforms a larger, unengaged one. Track engagement metrics alongside size. Removing inactive subscribers often improves deliverability and engagement rates.