Formula
Blended annual probability = observed rate × internal weight + external estimate × (1 − weight); horizon probability = 1 − (1 − annual probability)^years.
What the result means
The main result translates the entered assumptions into a consistent planning estimate. Supporting results show the major components so you can identify which input drives the outcome.
This calculator is an educational planning tool. It does not determine coverage, liability, compliance, a statutory deadline, or a guaranteed outcome.