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Cost variance compares the budgeted value of completed project work with its actual cost. Calculate it by work package, reconcile the total, and distinguish its sign from an accounting budget variance.
Cost variance in earned value management is earned value minus actual cost: the budgeted value of completed work less what that work cost. Positive is favorable; negative is unfavorable. It compares cost with progress, so an unfinished project can have money left in its budget and still be overrunning the work it has completed.
Cost variance (CV) = Earned value (EV) − Actual cost (AC)
Earned value = Approved work-package budget × Measured completion fraction
The Department of Energy's EVMS Gold Card defines CV as EV minus AC and identifies earned value as the budgeted cost of work performed. The completion formula above applies to this example's progress method; use the approved earning method for each real work package.
Earned value is neither revenue nor a supplier's invoice amount. It puts completed scope into the dollars originally budgeted for that scope. Actual cost uses the corresponding incurred costs through the same reporting date.
The sign is the opposite of an accounting expense variance calculated as actual minus budget. In budget variance analysis, positive expense variance usually means overspending. Here, negative CV means overspending against earned work. Label the formula on the report so a reviewer cannot read the color correctly but the number backward.
Bring the approved cost baseline, the progress summary, and the actual-cost export. The useful reporting row identifies a project, work package, reporting date, approved budget, earned progress, actual cost, and accountable owner.
Use a stable work-package identifier to match the files. Package names alone can change between the planning workbook and the cost ledger. Keep the approved baseline version in the summary, and document authorized changes separately from performance against that baseline.
For progress, record evidence rather than an unsupported estimate. Accepted drawings, installed quantities, or completed test milestones can support the earning method. A manager's statement that a package is nearly finished does not establish how much budget it has earned.
For actual cost, include the same labor, material, subcontract, and overhead categories included in the budget. If an invoice has not arrived for work already performed, review the appropriate accrual with finance. Otherwise the comparison rewards invoice timing.
The Department of Energy's earned value overview describes EVM as integrating scope, cost, and schedule. That connection matters: spending alone cannot tell the project manager whether the completed scope justified the cost.
A US manufacturer reviews a plant upgrade on September 30, 2026. The example uses cumulative figures from project start. Dollars are shown without rounding, and progress is the approved measured completion fraction for each package.
| Work package | Approved budget (USD) | Measured completion | EV calculation (USD) | Earned value (USD) | Actual cost (USD) | CV: EV − AC (USD) |
|---|---|---|---|---|---|---|
| Design | 100,000 | 100% | 100,000 × 100% | 100,000 | 105,000 | -5,000 |
| Installation | 300,000 | 50% | 300,000 × 50% | 150,000 | 180,000 | -30,000 |
| Testing | 100,000 | 20% | 100,000 × 20% | 20,000 | 15,000 | 5,000 |
| Total | 500,000 | 270,000 | 300,000 | -30,000 |
Design earned $100,000 and cost $105,000, leaving an unfavorable $5,000. Installation earned $150,000 and cost $180,000, leaving an unfavorable $30,000. Testing earned $20,000 and cost $15,000, contributing a favorable $5,000.
Installation is the first investigation. Ask whether more labor hours were needed than expected, subcontract rates changed, or rework was charged to the package. The CV locates the gap; the underlying time and invoice rows establish its cause.
The project has spent $300,000 against a full budget of $500,000. Subtracting those figures gives $200,000 of unspent budget, but it does not show cost performance. The relevant comparison is $270,000 of earned work against $300,000 of incurred cost.
Calculate CV both ways. The sum of package variances must equal the difference between project totals:
Package check: -5,000 − 30,000 + 5,000 = -30,000
Project check: 270,000 − 300,000 = -30,000
Then reconcile the $300,000 actual-cost total with the project ledger for the same cutoff, including the identified accruals. Reconcile the $500,000 approved budget with the selected baseline. Confirm that package progress belongs to that reporting date rather than a later operational update.
If the organization also reports CV as a percentage, disclose its denominator. The DOE Gold Card uses CV divided by earned value. For this example, -30,000 / 270,000 = -11.1%, rounded to one decimal place. Cost performance index is 270,000 / 300,000 = 0.90, shown to two decimals.
Those measures answer different questions. CV shows the dollar gap. CV percentage scales that gap to earned work. CPI shows earned budget value per dollar of actual cost. Do not average package percentages to obtain a project percentage; calculate it from the project totals.
Cumulative CV shows the position to date, but a project manager also needs the period movement. Subtract the previous cumulative report from the current one before judging recent performance.
| Reporting basis | Earned value (USD) | Actual cost (USD) | CV (USD) |
|---|---|---|---|
| Previous cumulative report | 220,000 | 240,000 | -20,000 |
| Current cumulative report | 270,000 | 300,000 | -30,000 |
| Movement between reports | 50,000 | 60,000 | -10,000 |
The current period earned $50,000 and incurred $60,000. Its unfavorable $10,000 explains the movement from negative $20,000 to negative $30,000. A cumulative number alone would conceal whether the latest work improved or worsened the position.
The controller owns the cost reconciliation, the package owner supports progress and explains the cause, and the project manager assigns corrective action. A favorable variance still needs review when progress is uncertain or unpaid costs are missing. For broader account and departmental investigations, use cost variance analysis.
Upload a project budget, progress summary, and actual-cost file, or bring a Google Sheet, so Covirage can map their columns. Its tools compute and check earned value and cost variance from the supplied work-package figures; the external AI model explains the result with every figure traced to its rows. Create a free Covirage account and bring a sample of your own data.
See project cost control for the supporting finance workflow.
Under the earned value convention, yes: positive cost variance means earned value exceeds actual cost for the work performed. Check that progress is supported and costs are complete before treating the difference as a saving. Missing invoices can temporarily make performance look better.
Cost variance is the dollar difference between earned value and actual cost. Cost performance index divides earned value by actual cost, expressing cost efficiency as a ratio. Calculate each from the same scope and reporting date so the two measures describe the same work.
Yes. Spending less than the entire project budget says little about efficiency while work remains unfinished. Negative cost variance means the work completed so far cost more than its approved budgeted value, even though the total project budget has not yet been spent.
Use the costs of work performed through the reporting date, including supported accruals under the project's accounting policy. Payments alone can lag the work. Finance should reconcile the actual-cost summary with the ledger and identify any estimates awaiting final invoices.