Cost to complete

Cost to complete is where the forecast stops being historical.

Actual cost tells you what has happened. Cost to complete forces the project team to quantify what is still expected to happen before the job is finished.

The basic commercial equation

Incurred

Actual cost to date

Costs already recognised against the project.

Remaining

Forecast cost to complete

Expected cost still required to finish each work package and cost category.

Outcome

Forecast final cost

Actual cost plus the remaining cost required to complete the project.

Why builders get caught

Committed cost is useful, but it is not automatically the same as final cost. Packages can be incomplete, exclusions can sit outside a subcontract, labour can remain uncommitted and provisional scope can move.

A cost-to-complete review therefore needs to ask whether each remaining allowance is commercially sufficient, not merely whether a purchase order exists.

When an allowance should move

  • A trade quote exceeds the residual budget.
  • A subcontract package is awarded but excludes known scope.
  • A material rate or quantity has changed.
  • Rework, delay or site conditions create additional expected cost.
  • A saving is genuinely locked in and no longer required elsewhere.
Forecast final cost = actual cost to date + realistic remaining cost. It should not be forced back to budget just because the budget is more comfortable.

What a useful review produces

Current variance

Where forecast cost differs from adjusted budget.

Reason

The commercial driver behind the variance, not merely the accounting code.

Action

What can still be negotiated, re-scoped, recovered or controlled.

Related workflow

Want the full project position rather than one formula?

BuilderForecast combines cost to complete with budget, commitments, variations and reporting so the forecast is maintained as the project changes.

Related resources