How the Flood Insurance Rate Index is calculated
The index reports what flood insurance was actually quoted at, taken from quotes that carriers returned to property owners through Insurox, a licensed insurance agency.
Where the numbers come from
When someone asks Insurox for flood insurance quotes, their property is sent to the private flood carriers we work with and to the National Flood Insurance Program. Each price that comes back is one carrier quote. The index is built on 150,000+ carrier quotes since 2020. No carrier is named in the index and no individual quote is ever shown.
A property is placed by the address being insured, not the owner's mailing address. Test quotes and quotes without a price are left out.
What each number means
- Lowest private quote
- For each property, the cheapest quote any private carrier returned. The index shows the median of those across properties. It answers: what would a typical shopper pay if they took the best private offer?
- Typical private quote
- For each property, the middle quote among the private carriers that priced it, counting one quote per carrier. The index shows the median across properties. It answers: what does a private carrier usually quote here?
- NFIP quote
- The median quote for the National Flood Insurance Program, the federal program sold through participating insurers.
- Private compared with NFIP
- Calculated only on properties that received both a private and an NFIP quote, and only where the coverage asked for fits within the NFIP maximums ($250,000 building and $100,000 contents for a home, $500,000 each for a commercial property). That keeps both prices covering the same amounts. The percentage is the median difference across those properties.
All figures are annual premiums including fees and taxes shown on the quote. A private quote that offered less building coverage than the owner asked for is not counted.
Time period and updates
Headline figures cover the trailing 24 months and are recalculated every night, so each day's index includes the newest quotes and drops the oldest. The trend chart uses calendar years, quarters and months from 2020 on, and the current one runs up to the latest update. A year, quarter or month is only drawn when it clears the same minimum as a place does, so some places have a yearly trend but no monthly one, and a dashed line marks a stretch with too few quotes to report.
When a place is published
A state, county or ZIP code gets its own figures only when at least 20 different properties were quoted there in the period. Each individual figure also needs at least 20 quotes of its own kind behind it, so a place can show private quotes without an NFIP comparison. Below that, the index shows the next larger area and says so. Figures for places close to the minimum move more from one update to the next than figures for places with hundreds of quotes.
What the index does not tell you
- It is not what people pay on average. It measures quotes, and people who ask for flood quotes are more likely to be in a high-risk zone or to need coverage for a mortgage. In the current edition 69% of quoted properties were in a high-risk A zone.
- It is not a quote for your property. Flood zone, elevation, foundation, coverage and deductible all move the price.
- It does not cover excess flood insurance.
- Private flood policies and NFIP policies differ in what they cover, so a lower price is not always the better policy.
Citing the index
Insurox Flood Insurance Rate Index, www.insurox.com/flood-rate-index, edition of October 9, 2026. Questions about the data can go to [email protected].