Email List Decay Study
An analysis of how email lists lose reachable addresses over time, the compounding effect of monthly decay, and what it means for sending cadence.
Key findings
2-3%
Monthly decay rate of a typical list
Source: Industry benchmark
~25-30%
Of a list can go stale in a year at that rate
Source: Derived
Highest
Decay in old and re-engagement segments
Source: Industry benchmark
Why lists decay
People change jobs and addresses, abandon mailboxes, and enter typos at signup. Each month a few percent of any list becomes undeliverable, and the effect compounds, so an unmaintained list loses a meaningful share of its reach within a year.
Decay hits old segments hardest
The oldest and least-engaged parts of a list decay fastest, which is exactly the segment marketers target with re-engagement campaigns. Verifying before those sends prevents a spike in bounces.
Keeping a list reachable
Regular verification removes decayed addresses before they bounce, and real-time verification at signup slows the inflow of bad data. Together they keep deliverability steady over time.
Methodology
Decay rates are widely-cited industry benchmark ranges. The annual figure is derived by compounding a 2 to 3% monthly rate over twelve months. Use the free list decay calculator to model your own list.
Frequently asked questions
How fast does an email list decay?
How do I slow list decay?
Put the data to work
Verify your list and protect deliverability with 1,000 free credits.