Business interruption calculator
Estimate your potential business interruption exposure — the financial impact of being unable to trade for a period after a covered event such as fire or flood.
Check your policy — the correct basis depends on how your BI sum insured is defined.
Be realistic — rebuilding, restocking, and re-acquiring customers can take longer than you think.
Add a buffer if your business has peak seasons — e.g. 15% if Q4 is your strongest quarter.
Extra costs to keep trading — e.g. alternative premises, equipment hire.
Assumptions and methodology
Estimated BI need = (monthly gross profit or fixed-cost basis × recovery months) + payroll (if included) + increased cost of working + seasonality buffer. Cash reserves are shown separately and only deducted if the user opts to view net exposure. A broker or adviser should help you define the appropriate BI basis (gross profit vs revenue) for your policy.
Common mistakes to avoid
- ✕Under-buying the indemnity period — if recovery takes 18 months but your policy only covers 12, you bear the remaining loss.
- ✕Choosing revenue instead of gross profit as the BI basis — check which basis your policy uses.
- ✕Forgetting payroll as a fixed cost if you want to retain staff during a closure.
- ✕Not considering seasonality — a business that earns most of its income in Q4 needs a higher BI sum if an event occurs in that period.
Frequently asked questions
A gross profit basis covers the gross profit you lose (revenue minus variable costs). A revenue basis covers total lost revenue. The appropriate basis depends on your business and policy wording — seek advice from a broker.
The indemnity period is the maximum time your BI policy will pay out. Choose a period that reflects the realistic time to get your business back to pre-loss trading levels — 12 months is often not enough.
Standard BI policies are typically triggered by physical damage to your premises. Non-damage events (pandemic, supplier failure) are usually only covered if you have specific extensions. Check your policy carefully.
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Disclaimer
This is a simplified estimate based on the assumptions shown above. It isn't a quote, and a real insurer may arrive at a different figure. Use it as a starting point, then check the details with your insurer or adviser.