Contract Price
The contract price is the agreed amount payable to the builder under the building contract for the scope of work described in the contract documents.
The contract price covers the documented scope only. Anything outside that scope, or any change instructed after signing, is dealt with as a variation and adjusts the price.
Two mechanisms commonly sit inside the price and are frequently misread. A provisional sum is an allowance for work that cannot yet be priced accurately, and a prime cost item is an allowance for an item not yet selected, such as tapware or appliances. Both are estimates and both are adjusted to actual cost.
The most reliable way to keep the final figure close to the contract price is complete documentation and finalised selections before signing. Most cost growth in residential projects originates in decisions deferred into construction.