time and materials

With time and materials billing, the final amount is known only after some or all of the work has been completed. The contractor records the time, materials and other costs required and bills them according to the agreement. This pricing model is used in maintenance, construction and professional services, among other areas.

How does time and materials billing work?

The client and contractor agree in advance on rates and which costs may be charged. They often also agree on an estimate or budget. Hours and expenses are recorded during the work. The invoice is based on those records, for example by multiplying hours worked by the agreed hourly rate.

Clear records of time and costs explain the amount charged. Regular progress discussions help identify deviations from the estimate early. Time and materials billing alone does not guarantee a project will stay within a particular budget; that requires additional agreements.

Actual costs, estimates and fixed prices

An estimate calculates expected costs in advance. It helps make decisions about scope and priorities. Time and materials billing uses actual costs calculated afterwards. Both can be used together: the estimate provides guidance, while the final calculation shows what the work actually cost.

With a fixed price, the parties agree on one amount for a clearly defined result. The risk of more or less work is then distributed differently. The appropriate model depends on how clearly the work is defined and how much uncertainty remains during delivery.