AI for Cost Estimation
Use AI to generate preliminary cost estimates, benchmark rates, and validate pricing assumptions faster.
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3 AI workflows for cost estimation
How AI helps with cost estimation
AI helps with cost estimation by turning your quantities, rates and assumptions into a structured cost plan, bill of quantities or pricing schedule, and by checking the arithmetic and spotting gaps. It's good at the layout: elemental cost plans following NRM1, bill items following NRM2, and tender pricing schedules with preliminaries, overheads and qualifications.
The weak point is the numbers. A general AI tool doesn't know current rates in your region, and it will give you confident figures that may be out of date, from another country or made up. It can't reliably measure from drawings, and it can't judge risk, the market or how keen to be on a tender. Rates should come from your own cost data, current quotes or a recognised benchmarking source.
Start with one estimate you're already working on. Give it your own quantities and rates, use a business account with data controls switched on, not a personal one, and check every line and total before anyone relies on it.
Where AI helps most
- Preliminary cost plans: an elemental breakdown following the NRM1 structure, using your benchmark rates and allowances.
- Bills of quantities: item descriptions, units and coverage set out in the NRM2 structure, from quantities you've measured.
- Bid pricing schedules: line items, preliminaries, overheads and profit, assumptions and qualifications laid out for tender.
- Tender document reviews: flagging cost-significant items in the specification and preliminaries, such as phasing, working hours or access limits.
- Checking: spotting missing elements, mismatched units, double counting and arithmetic errors.
- Assumptions and exclusions: drafting the list that goes with your estimate, so the client knows what the figure covers.
Where to be careful
- Rates: never use a rate the tool suggests without a source, and adjust every rate for location and date.
- Quantities: don't trust quantities it reads off drawings or PDFs. Measure them yourself or check them.
- Judgement: contingency, risk allowances, inflation and the final tender figure are commercial decisions for someone who knows the job and the market.
- Data: tender documents and your rates are commercially sensitive. Keep them in a business account with data controls, never a personal one.
Frequently asked questions
- What is the difference between a cost estimate and a cost plan?
- An estimate is a forecast of what the project will cost at a given stage. A cost plan breaks that figure down by element and becomes the budget the design is checked against as it develops. NRM1 covers both, from early order of cost estimates to formal cost plans.
- What is NRM in construction?
- The RICS New Rules of Measurement. NRM1 covers order of cost estimating and cost planning, NRM2 covers detailed measurement for building works, such as bills of quantities, and NRM3 covers maintenance works. Using them means everyone measures and describes work the same way.
- Can AI produce an accurate construction estimate?
- Only as accurate as the quantities and rates you give it. It's good at structure, checking and presentation, but rates it supplies itself can't be trusted. Treat its output as a draft for a qualified estimator or QS to check.
- How do you price preliminaries?
- Build them from the programme and the site set-up: site staff, welfare, hoarding, temporary services, plant, insurances and fees. Split them into fixed and time-related costs, so you can adjust them if the programme changes. AI can give you a checklist of items, but the durations and costs come from you.
- What is a bill of quantities?
- A document listing the work item by item, measured to a standard method such as NRM2, with a description, unit and quantity for each. Every tenderer prices the same list, which makes tenders easier to compare and gives a basis for valuing changes later.
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