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Percentage Catastrophe Deductible Calculator

A percentage catastrophe deductible is calculated from the base stated by the policy, not necessarily from the property's purchase price or the total portfolio value. Enter the policy base and percentage to display the raw dollar amount, then add a policy minimum or cap only when the wording provides one. This arithmetic is not a quote, coverage interpretation, or recommendation.

Key takeaways

  • Confirm the deductible percentage base and allocation in the policy or proposal.
  • Model a minimum and cap only when the policy actually states them.
  • Compare the dollar retention with available liquidity and lender terms separately.

Confirm the percentage base first

Policies can define a percentage deductible by reference to a building value, location value, reported value, total insured value, or another amount. The same percentage can therefore create different dollar retentions. Ask the carrier or broker to identify the exact base and when it is measured.

Do not use purchase price, assessed value, loan balance, or an unverified replacement estimate merely because it is convenient. The calculator cannot tell which value a policy uses.

Account for a stated minimum or cap

Some deductible provisions may include a minimum dollar amount or a cap, but those features are not universal. Enter them only when the proposal or policy supplies the value, and check whether the provision applies per building, location, occurrence, or another unit.

The calculator applies the minimum after the percentage arithmetic and applies the cap afterward. That order is a transparent modeling convention; the policy wording controls if it specifies a different calculation.

Place the result in catastrophe context

Flood, earthquake, wind, named storm, wildfire, hail, and other catastrophe terms vary by location, form, endorsement, and market. FEMA's flood maps and National Risk Index, along with USGS earthquake information, can inform hazard research but do not state whether a loss is covered or what deductible applies.

  • Check whether multiple locations can be affected by one occurrence.
  • Ask how a shared limit, sublimit, or aggregate interacts with the deductible.
  • Document the assumed base and date beside every scenario.

Review the retained loss

Use the output to ask better questions about liquidity, financing, lender requirements, and portfolio concentration. A lower premium is not automatically a better result if the retained catastrophe loss exceeds what the owner can fund.

Review the issued declarations, endorsements, definitions, exclusions, and deductible schedule. No calculator output changes the policy or guarantees claim payment.

Hypothetical: Hypothetical: different bases

Two proposals use the same percentage but different stated bases. Their dollar deductibles differ even though the percentage is identical. The owner should compare the actual policy definitions rather than the percentage alone.

Hypothetical: Hypothetical: minimum controls

A small location produces a raw percentage amount below the stated minimum. The planning output shows the minimum-controlled result, subject to confirming that the minimum applies to the same event and unit of insurance.

Questions owners ask

Is a percentage deductible based on market value?

Not necessarily. The policy or proposal defines the base. It may be a building, location, reported, or another value, so ask for the wording.

Does the calculator quote insurance?

No. It only applies the numbers entered. Premium, coverage, eligibility, policy wording, and claim response require an actual insurance review.

Can I enter a zero minimum or cap?

Leave an inapplicable minimum or cap blank. A zero base or percentage is not a meaningful catastrophe-deductible scenario, and a cap should be a positive policy value.

Sources

General educational information, not legal, actuarial, or policy-specific advice. Actual coverage depends on the policy form, endorsements, limits, deductibles, exclusions, jurisdiction, and facts. Submitting information does not bind coverage or guarantee carrier approval.