What does a quantity surveyor do?
Manages the money on a construction project for the party that appoints them: measuring and pricing the work, running payment applications or assessments, valuing changes, forecasting cost to completion and agreeing the final account.
Updated: 15 September 2026. By Jack Butler-Kettle, Quantity Surveyor & Claims Consultant.
The answer
A quantity surveyor manages the commercial side of a building or engineering project. Before construction that means measuring the work from the drawings, producing bills of quantities or pricing schedules, preparing or checking tender prices, and advising on the contract and its payment terms. During construction it means running the payment cycle, either applying for payment and pricing variations for a contractor or subcontractor, or assessing applications and certifying sums for a client, together with keeping the cost and value reconciled, forecasting the final cost, and managing the notices the contract requires. At the end it means agreeing the final account and releasing retention. The same skills are used in claims work, where the quantity surveyor calculates what a delay or a change has cost from the records. The job is the same in outline whichever side the surveyor sits on; what changes is whose money they are protecting, and a surveyor who has sat on both sides reads the other side's paperwork faster.
Example
The situation
A £2m residential subcontract is let, and the subcontractor's quantity surveyor carries it from tender to final account while the main contractor's quantity surveyor does the mirror image of each step.
What happens
- The subcontractor's quantity surveyor checks the tender before it goes in and reads the subcontract's amended payment terms.
- A measured application is submitted every month with the variations priced.
- Each Payment Notice is answered against the measure, and the variation register is kept current.
- The final account is forecast each month for the directors.
- The account is closed with the retention released.
The outcome
The subcontract runs from tender to closed account with each step measured, answered and recorded, and the main contractor's quantity surveyor mirrors each one from the other side.
The Quantity Surveying page lists what we take on, by stage and by audience.