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Estimating & costing

Escalate an estimate with price indices

Bring base-date rates forward to the midpoint of construction using published cost indices, so the number reflects when the money is really spent rather than the day the rate was set.

4 steps9 minCost consultant / QSGeneral contractorDeveloper / client

How it works, step by step

4 steps across the platform - what you do at each one, and why it matters.

1

Set base and target dates

Price Index

Fix the base date of your rates and the target date to escalate to, usually the midpoint of the construction period where spend is heaviest.

Why: Escalating to the midpoint rather than the start or the end is the fair average across the spend curve. Getting these two dates right is most of the accuracy of the whole exercise.

InBase-date estimateConstruction datesOutBase and target dates
2

Read the escalation factor

Price Index

Pick the index series that best matches the work - building, civils, or a trade-specific one - and read the factor between the base and target dates.

Why: The right series matters: labour, steel and energy do not move together. Choosing an index that fits the work is what makes the escalation credible rather than a blanket guess.

InBase and target datesPublished index seriesOutEscalation factor
3

Apply it to the bill

BOQ

Apply the factor to the bill and read the escalated total next to the base figure, so the uplift is a line you can point at rather than a number folded into the rates.

Why: Showing the base and the escalated total side by side keeps the client's trust. It also lets you re-run the uplift cleanly if the start date slips again.

InEscalation factorBase-date billOutEscalated total
4

Record it in the basis

Basis of Estimate

Write the base date, the index series and the factor into the basis of estimate so anyone reading the price later knows exactly how it was escalated.

Why: An escalation nobody can reconstruct is an escalation nobody trusts. Recording the working is what turns a defensible method into an auditable one.

InEscalated totalOutRecorded basis

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