How to Prepare a Bill of Quantities (BQ)

A Bill of Quantities (BQ) is an itemised list of every material, labour item and cost element needed to complete a project — organised by section (substructure, superstructure, roofing, finishes, and so on), with a quantity, unit, rate and total for each item.

Why it matters

• It turns a design into a measurable, comparable cost — you can get like-for-like quotes from different contractors
• It's the reference document for tracking what's been paid for versus what's actually been built
• It reduces disputes, because scope and quantities are documented upfront rather than agreed verbally
• It's required for most formal tendering and financing processes

How a professional BQ is prepared

• Start from finalised architectural and structural drawings — a BQ prepared before the design is settled will need revision
• Measure quantities section by section, following a standard method of measurement
• Apply current market rates for materials and labour in your area
• Add preliminaries (site setup, supervision, temporary works) and a contingency allowance
• Have it reviewed by a quantity surveyor before it's used to tender or budget

Preliminary vs. professional BQs

A preliminary BQ — like the one our BQ Estimator produces — gives you section-level figures for early planning. It is not a substitute for a professional BQ measured from your actual drawings, which is what you should tender or budget against once your design is final.