In the construction industry, a quantity surveyor (QS) is a professional with expert knowledge of construction costs and contracting. Qualified professional quantity surveyors can be known as Chartered Surveyors (Members and Fellows of RICS) in the UK and Certified Quantity Surveyors (a designation of the Australian Institute of Quantity Surveyors) in Australia and other countries. In some countries, including Canada, South Africa, Kenya and Mauritius, qualified quantity surveyors are known as Professional Quantity Surveyors, a title protected by law.

Quantity surveyors are responsible for managing all aspects of the contractual and financial side of construction projects. They help to ensure that the construction project is completed within its projected budget. Quantity surveyors are also hired by contractors to help with the valuation of construction work for the contractor, help with bidding and project budgeting, and the submission of bills to the client.

The duties of a quantity surveyor are as follows:

A university degree or diploma alone does not allow one to register as a Chartered Quantity Surveyor. Usually, anyone looking to qualify as a Chartered Quantity Surveyor, Certified Quantity Surveyor must hold appropriate educational qualifications and work experience, and must pass a professional competence assessment.

The RICS requires an RICS approved degree, several years of practical experience, and passing the Assessment of Professional Competence (APC) to qualify as a Chartered Quantity Surveyor. Some candidates may be entitled to qualify through extensive experience and reciprocity agreements.