Email List Decay Calculator

Email list decay is the silent erosion of one of your most valuable marketing assets. Industry data suggests email lists degrade by 22 to 30 percent per year through a combination of unsubscribes, bounces, spam complaints, and inactive subscribers. For a brand with 25,000 subscribers generating $1.80 per subscriber per month, losing even 5,000 subscribers represents $108,000 in lost annual email revenue.

This calculator models your list growth or decline over 12 months by tracking the balance between new subscriber acquisition and monthly losses. The net monthly change tells you whether your list is growing or shrinking, and the projection table shows the trajectory month by month. Many brands are surprised to discover their list is actually shrinking despite active acquisition efforts because their unsubscribe rate exceeds their growth rate.

The annual revenue impact quantifies the cost of decay in dollars, making it easy to justify investment in list growth and retention. If losing 200 subscribers per month costs $4,320 in annual revenue, spending $2,000 per month on list growth strategies that add 500 new subscribers is clearly worth it.

To slow list decay, focus on reducing unsubscribe triggers: segment your sends so subscribers only receive relevant content, manage send frequency to avoid fatigue, optimize mobile rendering, and provide genuine value in every email rather than purely promotional content. To accelerate growth, optimize your site popup conversion rate, offer compelling lead magnets, add email capture to checkout, and consider referral incentives for existing subscribers. The healthiest ecommerce email programs maintain a net positive growth rate of 2 to 5 percent per month.