A cost-plus contract is an agreement between two parties in which one party agrees to reimburse the other party for expenses they incur, plus a fixed rate of return, as compensation for their services. This type of contract can be used in a variety of fields and situations, and is often employed when the budget a business or individual has to work with is limited or their is a high probability that actual costs may be less than anticipated.

Cost-plus contracts typically involve the contractor providing the contracting party with proof of all related costs and expenses, including those that are both direct and indirect, in order to receive the payment outlined in the agreement. This may include necessary labour, materials, tools, and equipment.

It is usual for a cost-plus contract to include specific clauses to help protect both parties from any unforeseen costs or losses, for example by listing the measures that must be taken should any associated costs become significantly greater than originally expected. Provisions can also be made for profit to be adjusted if savings are made during the course of the job. Including these provisions in a contract offers greater peace of mind to both parties.

Cost-plus contracts are often used in construction, engineering, and manufacturing projects, and they have the added benefit of offering transparency, as it allows the contracting party to track and verify all costs that are incurred during the course of the project. This can be especially beneficial in large projects where multiple stakeholders and entities are involved, as it ensures that all costs are accounted for prior to the payment process.

Cost-plus arrangements are especially beneficial when used for complex projects that are subject to pricing risk, and in situations where subjective judgment and varying opinions regarding quality, cost estimation, and technical capability come into play. By using a cost-plus approach, those involved in the project can focus on completing the task, with the assurance that all related costs are covered, and that any additional or extra costs incurred due to unforeseen circumstances will not place a prohibitive burden on the project itself.

Overall, cost-plus contracts are extremely useful in situations where the budget for a project is limited and/or where the exact costs of the project cannot be easily determined. They offer a safe and reliable approach to contracting services, and help to ensure that both parties are adequately compensated for their efforts.