- Enter an annual loss probability. Use a scenario probability between 0% and 100%.
- Choose a number of years. Set the time horizon over which you want to accumulate the annual risk assumption.
- Read the at-least-one-loss result. This is the cumulative probability under a constant annual rate.
- Check the no-loss probability. This is the complement of the main result for the same horizon.
- Treat expected count as an average. Annual probability multiplied by years is shown as a simple event-count expectation, not as a guaranteed number of claims.
Home Insurance Loss Probability Calculator
Estimate the probability of at least one home insurance loss over a chosen number of years from an assumed annual loss probability. The tool also reports the probability of no modeled loss and the simple expected number of events, helping you see how repeated annual exposure changes a long-term risk scenario. The calculation is intentionally assumption-driven. It does not use an address, catastrophe model, property characteristics, or insurer loss data, so the output should be treated as a mathematical translation of the annual rate you enter rather than a property-specific forecast.
Enter your assumptions
%
years
Result
—
Probability of at least one modeled home loss
Probability of no modeled loss—
Simple expected event count—
Annual probability used—
Time horizon—
No-loss probability = (1 − p)^nAt-least-one-loss probability = 1 − (1 − p)^nExpected event count = p × n
Where:
- p = assumed annual probability of a modeled home loss
- n = number of years
Assumptions: The annual probability is constant and yearly loss events are treated as independent. Actual home-loss frequency depends on property, location, hazards, maintenance, coverage definitions, and other factors.
What the result means
The main percentage is the probability of one or more modeled events during the selected horizon if the same independent annual probability applies each year.
This is not an insurer’s catastrophe model or a location-specific risk score.
Given: Annual modeled home-loss probability = 5%; horizon = 10 years.
Calculation: No-loss probability = (1 − 0.05)^10 = 0.95^10 ≈ 0.5987, or 59.87%. At-least-one-loss probability = 1 − 0.5987 = 0.4013, or 40.13%. Expected event count = 0.05 × 10 = 0.50.
Result: The modeled probability of at least one home loss over 10 years is about 40.1%.
Interpretation: A 5% annual assumption accumulates to a substantially larger chance of at least one event over a decade, even though the expected count remains 0.5.
Why is the 10-year probability not simply 50% when the annual rate is 5%?
Multiplying 5% by 10 gives an expected event count of 0.5, not the exact probability of at least one event. The complement formula is used for the cumulative probability.
Can I use a probability from my insurer?
You can enter any annual probability that is meaningful for your scenario, but make sure you understand what event definition and time period that probability represents.
What if home risk changes over time?
This model does not vary the rate by year. You can run separate scenarios, but a changing-risk model would require year-specific probabilities.
Does one claim make another claim more or less likely?
The calculator assumes independence, so it does not model that relationship. Real-world conditions can create correlation across years.
How is this different from expected claim value?
Loss probability describes how likely one or more events are. Expected claim value adds a dollar payout assumption and weights it by probability.