Construction Costs vs Project Costs: Where One Ends and the Other Begins

By

Josh Krissansen

Last Updated Aug 20, 2026

By

Josh Krissansen

Construction costs are the costs payable to the builder under the head contract. Project costs are broader, covering everything it takes to get the project built, including all expenditures the principal carries outside that contract.

That distinction has direct consequences for how budgets are structured and where scope risk sits. Budgets built on construction cost rates alone routinely arrive at tender with a significant funding gap. Consultant fees, authority charges, and FF&E were never included because no one defined who was carrying them. That gap doesn't disappear. It either gets found before award or it surfaces as a variation after it .

This guide will cover what each category includes and how the boundary between them works in practice so that you can structure budgets, define contract scope, and manage cost reporting with confidence.

What are construction costs?

Construction costs cover everything included in the head contract sum. That includes labour, materials, subcontractors, preliminaries, and the contractor's margin.

Usually if you see it appear in a progress claim, it's a construction cost.

A useful way to see where construction costs end is to look at what a standard benchmarking rate actually captures.

Rawlinsons $/m² cost estimate guide, captures labour, materials, subcontractors, preliminaries, and margin, but has nothing in it for consultant fees, authority charges, geotechnical, financing, or FF&E. That makes it a construction cost rate rather than a project cost rate. 

What are project costs?

Project costs include everything it takes to get the project built, not just what the builder charges.

The full head contract sum (i.e. all construction costs) sits inside the project cost, but project costs also contain significant expenditures that are not part of the construction contract. All of those costs are carried and managed by the principal, not the head contractor.

Expenditure that the principal carries outside of the construction contract includes:

• Consultant and design fees
• Authority and statutory charges
• Geotechnical and survey
• Furniture, fixtures, and equipment
• Financing costs
• Client-side insurances
• Relocation and commissioning

This means that a $50 million head contract doesn’t mean a $50 million project. Consultant fees, authority charges, financing, and FF&E can add materially to the project cost. Rawlinsons guidance and AIQS benchmarks suggest principal-side costs on commercial projects commonly sit in the range of 15–25% on top of the construction cost, though this varies significantly by project type, procurement model, and client requirements. 

Pro tip: Project costs do not appear in the contractor's progress claims and are tracked separately in the principal's project budget.

The boundary between construction costs and project costs

The line between these two cost categories is not always clean.

Some items can legitimately sit in either bucket depending on how the contract is written, such as:

• Builder's work in connection with principal-supplied specialist contractors
• Authority fees the builder pays on behalf of the principal
• FF&E procured through the builder as a provisional sum

When the contract does not clearly state who carries items that sit on the boundary, both sides assume the other has it. That assumption becomes a problem mid-delivery as a variation, causing problems for both the budget and the schedule.

This is why explicit allocation in tender documentation matters.

AS 4000-1997 defines how the contract sum is established and how it is adjusted through variations and provisional sums, but the framework only protects you if the boundary items are named and allocated before contractors price the job.

The decisions that keep construction costs and project costs separate

Making sure everyone on the project understands the line between construction costs and project costs is an important first step. But that understanding alone doesn't protect the budget.

There are several decisions that need to be made at each stage of the project lifecycle, and missing them is what causes issues like budget gaps and reporting confusion.

Here’s what needs to happen at each stage.

Feasibility

The budget structure established at feasibility sets the pattern for everything that follows.

Establish that pattern by setting up two separate budget lines from the first cost plan: one for the construction cost, one for everything the principal carries outside it. 

Then, apply a separate contingency to each line, sized to the risk profile of that category. Principal-side costs like consultant fees and authority charges carry different risk than the construction cost, and a single blended contingency obscures that.

Finally, assign ownership explicitly: once engaged, the head contractor is generally responsible for the construction cost under the head contract, while the principal manages costs outside it.

Tender

Tender is where boundary items get allocated or left behind (and added later as variations).

Work through them specifically before contractors price the job. Builder's work in connection with principal-supplied specialist contractors, authority fees, and any loose FF&E or equipment should be clearly allocated, whether it is procured directly by the principal or through the builder as a provisional sum..

Write the allocation into the conditions of tender, not just the scope of works. If it is not named and allocated, both sides will price on their own assumption, and the gap will surface as a variation.

Contract award

Once the contract is executed, review the contract sum against the cost plan to confirm every boundary item has landed where it was allocated at tender. Check that provisional sums are set at realistic allowances rather than nominal figures that will require adjustment later. 

Delivery

During delivery, the contractor's progress claims and the principal's project budget are tracking different things and will never directly reconcile.

Set up a reporting framework that runs both in parallel. On the contractor side: the contract sum, approved variations, and forecast final cost. On the principal side: consultant fees, authority charges, FF&E, and financing tracked against the original feasibility allowance. 

Reconcile both to a consolidated project cost at each reporting period. The progress claim alone will never give you the full picture, because it only captures what the contractor is entitled to claim, not what the principal is spending outside the contract.

Construction costs vs project costs: Getting the boundary right is what keeps project budgets on track

Most budget blowouts on commercial projects are not caused by construction costs running over. They are caused by project costs that were never fully captured, principal-side expenditure that sat outside the head contract and outside anyone's cost plan until it became unavoidable. 

Getting the boundary right before feasibility is signed off is what prevents that. Everything else is recovery.

Written by

Josh Krissansen

106 articles

Josh Krissansen is a freelance writer with two years of experience contributing to Procore's educational library. He specialises in transforming complex construction concepts into clear, actionable insights for professionals in the industry.

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