How to use the email unsubscribe rate calculator
Unsubscribe rate is unsubscribes ÷ emails delivered, and the denominator being delivered mail rather than opens matters. Calculated per open, the same campaign looks several times worse, so this tool uses the delivered basis by default and only adds the per-open figure when you enter opens.
One campaign at 0.2% looks small, but it compounds and shrinks the list. Enter your current list size and the number of upcoming sends and you get the subscribers remaining and the cumulative unsubscribes if the same rate holds. This view leaves out new signups, so it shows the decline only.
When the rate climbs, check send frequency, segmentation and whether subject lines match the content inside. An acceptable level varies widely by industry and list source, so this calculator proposes no threshold and is built for comparison against your own past campaigns.
Frequently asked questions
The common industry basis is emails delivered. Using opens makes the number several times larger, so pick one basis and stay with it. This calculator shows the delivered basis by default and the per-open version separately.
No. It assumes the rate shown holds and no new subscribers arrive, so it measures only the decline. Your real list can be larger once new signups are added.