I-COSTA bill of quantities (BOQ) lists every item of work on a job with its quantity and unit, so that every contractor prices the same thing. In the UK most BOQs follow the RICS New Rules of Measurement (NRM2). Pricing one well is the difference between winning work you can deliver and winning work that loses money.
1. Read the tender documents first
Before you price anything, read the drawings, specification, preliminaries and contract terms. Note anything the BOQ does not cover, any provisional sums and prime cost (PC) sums, and any items you will need to qualify.
2. Check the quantities
Spot-check the main quantities against the drawings. If you find an error, raise a query rather than silently pricing around it. Check the BOQ total adds up and note where items are grouped by area or level, so your price can be tracked the same way later.
3. Split each item into labour, materials, plant and subcontract
Every rate is a build-up. For each item, work out how much labour, material and plant it needs per unit, or whether it will be subcontracted as a package.
| Element | How to price it |
|---|---|
| Labour | Output per hour (labour constant) × all-in hourly rate |
| Materials | Quantity per unit × current supplier price, plus waste and laps |
| Plant | Hire and fuel per unit, or as a preliminaries item for the whole job |
| Subcontract | The subcontractor's quotation for the package, checked like for like |
4. Use current prices, not last year's
Ask suppliers and subcontractors to price the actual items and quantities. UK construction material prices rose 6.4% in the year to August 2026, with structural steel up 21.2% (Department for Business and Trade), so a rate copied from an old job can quietly eat your margin. AI chatbots can help you draft, but they don't know today's prices from your suppliers.
5. Price preliminaries
Preliminaries cover the costs of running the site that are not tied to one item: site management, welfare, scaffolding, temporary works, insurance, skips and so on. Price them against the programme, not as a guessed percentage.
6. Add overheads, risk and margin
Add your company overheads, a risk allowance where the scope is uncertain, and your margin. Be clear whether you are using margin or markup:
Margin vs markup: a cost of £100 with a 20% markup sells at £120. To make a 20% margin (profit as a share of the selling price) it must sell at £125. Mixing the two up is one of the most common pricing errors.
7. Check the total and submit
Compare the total with your expectations and with similar jobs, check the biggest items again, and submit with clear qualifications and exclusions.
Common BOQ pricing mistakes
- Retyping the BOQ and losing a line or a decimal place
- Copying rates from an old job without checking current prices
- Confusing margin and markup
- Pricing preliminaries as a percentage instead of against the programme
- Losing track of the agreed price after the client negotiates
Pricing a BOQ in I-Cost
In I-Cost you import the client's Excel BOQ (or quantities from a BIM model), check it against its total, price each item at cost and selling rates, apply your margin and send the quotation, and copied rates are checked against what you have bought since. See construction estimating in I-Cost.
Questions
What is a BOQ in construction?
A bill of quantities lists every item of work on a project with its quantity and unit, usually measured to the RICS New Rules of Measurement (NRM2) in the UK, so contractors price the same scope.
What is the difference between margin and markup?
Markup is profit as a percentage of cost; margin is profit as a percentage of the selling price. A 20% markup on £100 gives £120; a 20% margin needs a selling price of £125.