The Bill of Quantities is the single most powerful document in a construction contract. Here is how to read one without a QS degree.
What a BOQ is
A Bill of Quantities is a measured list of every item of work in your project — quantities, units, rates and totals. It converts drawings into money, item by item, so that two contractors bidding on the same job are pricing exactly the same scope.
The five columns that matter
Every BOQ line has the same anatomy:
- Description — the exact work item and specification
- Unit — m², m³, linear metre, number or item
- Quantity — the measured amount taken off the drawings
- Rate — the price per unit, inclusive of labour, material and plant
- Amount — quantity multiplied by rate
Preliminaries are not padding
The preliminaries section covers site setup, hoarding, security, insurance, supervision and site welfare. It typically runs 8–12% of the contract sum. A bid with suspiciously low preliminaries is usually a bid that intends to recover the difference through variations later.
Use it after signing, too
The BOQ is your valuation tool for the whole build. Monthly certificates should reference BOQ line items and percentages complete. If your progress payments cannot be traced back to BOQ lines, you have lost cost control before the first slab.
Want these numbers for your own project?
Run the estimator for an indicative range, or send us the drawings and we'll return a costed BOQ.