What does a quantity surveyor do?

A quantity surveyor turns drawings, specifications, prices and site records into information people can use to make financial decisions about construction. The work changes as the design develops, a contractor is appointed and the project is built. A one-off estimate and a full commercial-management appointment involve different responsibilities.

For the meaning of the profession and how it differs from other surveying roles, start with what is a quantity surveyor?. This page concentrates on the tasks and documents you can expect.

Before construction: establish and test the budget. The QS reviews the brief, drawings, specification and available site information, then records what the estimate includes, excludes and assumes. An early estimate should make uncertainty visible; it is not a builder's fixed offer. As the design develops, a cost plan allocates the budget to elements of the work so options can be compared.

At tender: make prices comparable. A QS can help prepare pricing information, examine contractors' returns and identify omissions, qualifications and inconsistent allowances. Comparing only the totals can hide a significant difference in scope. The output is a tender comparison with clarifications and a recommendation based on the information available.

During construction: value work and track change. A client's QS may assess the value of work for payment; a contractor's or subcontractor's QS may prepare applications and substantiate the amount sought. They can measure changed work, apply the agreed valuation rules and maintain a variation register. They also report the anticipated final cost and explain movement against the budget.

At completion: reconcile the final account. The QS brings together the original price, adjustments, outstanding items, payments and retention. They identify agreed and disputed figures and support negotiations within their authority. The output is a traceable final-account reconciliation, with unresolved matters and release conditions still visible.

Typical outputs include a measurement take-off, estimate, cost plan and risk allowances. The project budget and cost-plan template shows a completed illustration and provides a blank working sheet. The estimate-versus-cost-plan comparison explains their different purposes.

See comparing construction tenders for the checks and a downloadable comparison template. The appointment should say who prepares the design and specification and who makes the final appointment decision.

Typical outputs are a payment assessment or application, change valuation, cost report and cash-flow forecast. A valuation is not automatically a payment notice: issuing notices and certifying payment must follow the actual contract and appointment. Our interim valuations and payment applications guide explains the distinction.

Use completion and final accounts for the closing process and its blank templates. Completion itself does not mean every claimed amount has been agreed or all retention is immediately payable.

A contractor may need tender pricing, subcontract procurement, applications, cost reporting or final-account support. The same professional discipline serves different commercial positions; the QS should be clear about whose interests they represent.

The RICS explanation of QS work describes cost advice across a project's stages. Check the actual appointment for responsibility for inspections, certification, contract administration, design, programme analysis and legal advice; none should be assumed from the title alone.

Our Construction cost estimating and planning service establishes the scope and assumptions behind the client’s construction budget. Name the decision you need help with, the output, available information, exclusions, delivery date and fee basis. Ask who checks the work and what information you must supply. A defined review can be more appropriate than a whole-project appointment.