Event Contingency Calculator
The expected loss from an event's main risks — each a probability and a cost — against the contingency reserve you have set, with the worst case, whether the reserve covers it, and whether an insurance premium is worth paying.
A risk is worth its probability times its cost: a 20% chance of an 8,000 wet-weather marquee is 1,600 of expected loss.
How the event contingency calculator works
A risk is worth its probability times its cost: a 20% chance of an 8,000 wet-weather marquee is 1,600 of expected loss. Add the risks and compare with the reserve. The reserve should cover the expected loss comfortably and the worst case at least partly; insurance transfers the worst case for a premium, and it pays when the premium is below what the risks are worth to you.
Formula: expected loss = Σ pᵢ × costᵢ; coverage = reserve / expected loss; insure if premium < expected loss + risk premium
Worked examples
| Inputs | Expected loss | Note |
|---|---|---|
| Three risks against a 10% reserve | 5,100 | the reserve covers it |
| A thin reserve | 5,100 | below the expected loss |
| Cheap insurance | 5,100 | worth buying |
FAQFrequently asked questions
How big should an event contingency be?
Ten per cent of the budget is the norm; the expected loss of the risks you can name is the floor. If the named risks alone exceed the reserve, the reserve is wrong.
What is expected loss?
Probability times cost, summed over the risks — what you would lose on average across many identical events. It is the fair value of the risks, and the number to compare a premium against.
When is event insurance worth it?
When the premium is below the expected loss, or when the worst case would be ruinous and you would rather pay a little extra to cap it. Cancellation cover for a large event usually passes the second test.
How do I estimate probabilities?
Weather from climate records for the date, vendor failure from experience — a few per cent — and attendance from past events. Round numbers are fine; the point is to rank the risks.
What else reduces risk?
Contracts with cancellation terms, deposits held back, a wet-weather plan agreed in advance and a second supplier on call. Each lowers a probability or a cost in this table.
Where these figures come from
- US FDA Food Code — food service guidance — holding and service context behind catering quantities
- US Food and Drug Administration — the federal food regulator
Last checked: September 2026. Portion and spacing figures are standard catering and event-industry conventions, stated on each page.