Calculate expected cost from maximum cost and probability, sum EMV across multiple risks, or estimate PERT cost from min, likely, and max values.

Use a known cost and its probability.

Illustrative example

Examples are hypothetical; they do not estimate your risk.

Expected Cost Formula

The following formula is used to calculate the Expected Cost for a single event where the cost is $0 if the event does not occur and the specified event cost (MC) if it does occur. 

EC = MC ร— P(x) / 100
  • Where EC is the Expected Cost ($)
  • MC is the cost if the event occurs ($) 
  • P(x) is the probability of incurring that cost (%) 

To calculate expected cost under this single-event model, multiply the cost if the event occurs by the probability of occurrence (expressed as a decimal, or divide the percent by 100).

How to Calculate Expected Cost?

The following example problems outline how to calculate Expected Cost.

Example Problem #1:

  1. First, select โ€œExpected cost ยท single eventโ€ and enter the cost if the event occurs ($), given as 5,000.
  2. Next, determine the probability of cost (%). The probability of cost (%) is provided as 70.
  3. Finally, calculate the Expected Cost using the equation above: 

EC = MC * P(x)/100

The values given above are inserted into the equation below:

EC = 5000 * 0.70 = 3500 ($)

FAQ

What is the importance of calculating Expected Cost in financial planning?

Calculating Expected Cost is useful in financial planning because it helps businesses and individuals estimate potential expenses associated with uncertain events (risk). This quantifies average cost impact. Expected cost alone is not a sufficient reserve for every outcome; budgets also need an appropriate assessment of tail risk.

Can Expected Cost calculations be applied to personal finance?

Yes. Individuals can use expected-cost (expected value) calculations to estimate potential costs of personal projects, investments, or purchases by considering the cost impact and the probability of incurring that cost. This can help in budgeting and saving for future expenses.

How does the probability of cost affect the Expected Cost?

For a single event where the cost is $0 if it does not occur and a specified cost if it does occur, the Expected Cost equals (cost if it occurs) ร— (probability of occurrence). A higher probability increases the Expected Cost, while a lower probability reduces it.