Escalate an estimate with price indices

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.

Pourquoi: 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.

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.

Pourquoi: 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.

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.

Pourquoi: 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.

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.

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