Part C is the most misunderstood factor. A contingency is a monetary provision for uncertainties about performing the work and unforeseeable costs to execute the defined scope of work. For example, a contractor may know what work must be done but not be confident that the precise execution requirements and limitations are known.

Contingencies are included in an estimate to create an appropriate level of probability for completing the project within the floor and ceiling threshold limits for that estimate. The cost allowances added to the estimate in Part C of the Cost Estimating Format represent financial protections for the final delivery of the eligible scope of work (developed in Parts A and B) defined during the engineering and design phase.