A provisional sum is an amount included in a BOQ or contract for work or items whose details are not yet known at the time of tender, which is later adjusted up or down to the actual cost.
Typical provisional sums cover items that are chosen late, such as tiles, sanitary fittings or lighting, or work that depends on site conditions, such as extra excavation.
The final account replaces each provisional sum with what was actually spent. Bidders should treat them as an allowance, not a fixed price.
Clients should keep provisional sums realistic. Too low, and the project looks cheaper than it is; the gap appears later as an overrun.
Budget a provisional item as its own BOQ line, then compare the vendor bills against it with budget vs actual and overrun alerts. See all features.
ARC PEM tracks your BOQ, vendor bills, labour attendance, contractor ledgers and GST across every project — live for the whole firm, on any phone or computer.
Join 30+ architecture and construction firms already using ARC PEM to track budgets, manage vendors, and generate professional reports — without a single spreadsheet.