What Is a Provisional Sum in Construction?
A provisional sum is an amount included in the contract price for work or costs that cannot yet be fully defined or priced at tender. It is a budget allowance, not a guaranteed payment: the sum is spent only as instructed, and the contract price is adjusted to the actual cost.
Why provisional sums are used
Some parts of a project are not designed or selected when the tender is issued, for example finishing selections, specialist packages or utility connections whose cost depends on third parties. A provisional sum holds a place for them in the tender total so all bidders price on the same basis.
How a provisional sum is used
The mechanism is set by the contract, but it usually works like this:
- The employer's representative issues an instruction on how, and how much of, the sum is to be used.
- The work is valued at actual cost or at rates agreed under the contract, sometimes with an allowance for the main contractor's attendance and profit.
- Any unspent amount is deducted from the contract price, and any overspend is added.
- Unused provisional sums are omitted, and the contractor is not entitled to the full amount.
Provisional sum versus contingency
A provisional sum is for work that is expected but not yet defined. A contingency is a reserve for unforeseen events and is held by the employer or in the budget. Keeping them separate prevents money being drawn for the wrong purpose and keeps the final account clear.
Provisional sums on Gulf projects
Gulf BOQs commonly include provisional sums, sometimes for named items such as testing, authority fees or nominated specialists. How they are instructed, whether main contractor profit and attendance apply, and how they are adjusted differ between contracts, so read the BOQ notes and the conditions.
How Arkan handles provisional sums
Provisional items are first-class in the BOQ module.
- BOQ items have a cost type of Lumpsum, Normal, Fixed or Provisional, and the grid can be filtered by cost type.
- Changes to the BOQ can be recorded as variations that carry through to payment requests.
- The BOQ shows item amounts and statuses so the provisional portion of the contract is visible.
Frequently asked questions
Is a provisional sum guaranteed to be paid to the contractor?
No. It is paid only to the extent the work is instructed and carried out, valued as the contract provides.
What is the difference between a provisional sum and a prime cost sum?
A provisional sum is for work not yet defined. A prime cost sum, in some standard forms, is for items to be supplied or carried out by a nominated party. Contract definitions vary, so check yours.
Who controls the spending of a provisional sum?
The employer's representative, through instructions, in line with the contract.
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Last updated: 2026-10-14. Definitions are general guidance. Your contract and project procedures govern.
