The plant incurred less fixed overhead than budgeted, yet the month-end report shows an unfavorable production volume variance. The variance measures how much fixed overhead the plant applied to actual output at its standard rate compared with the budget. Lower output can reduce that applied amount even when the plant spends less.
Subtract fixed overhead applied to actual production from budgeted fixed manufacturing overhead. Under that sign convention, a positive amount is unfavorable because output absorbed less than the budget. The applied amount uses standard activity allowed for the units produced (such as standard machine hours for the actual product mix).
Start with the approved fixed overhead rate
Take the period’s fixed manufacturing overhead budget and the approved activity base that went into the rate. The activity base is the denominator used to spread that budget across production, expressed in units such as machine hours. Divide the budget by that denominator. For a report tied to a specific cost center, use the same cost center and period for the rate, output, and budget.
ACCA’s fixed overhead absorption example separates the effect of output from the effect of fixed overhead expenditure. Its hour-based example uses standard hours for actual production when calculating the full volume effect. Keep the plant’s approved rate fixed for the comparison. Replacing its denominator with actual activity would change the question and could absorb the entire budget by construction.
A production plan and the denominator used for the standard rate can be different baselines. For example, the site might schedule a shorter month without changing the rate used for its internal report. Label both. Use the approved denominator for absorption and the applicable production plan when you report whether the factory made the units it scheduled.
Reconcile a smaller batch mix with lower spending
Assume one plant, one cost center, one month, and an approved standard fixed overhead rate that uses the same 6,000 machine hours as the original plan. The plant budgeted $120,000 in fixed manufacturing overhead. Product A uses two standard hours per finished unit and product B uses three. For this hypothetical calculation, the completed units are the approved basis for applied overhead, and no WIP adjustments or rate changes apply.
| Measure | Calculation | Result |
|---|---|---|
| Plan in units and standard hours | 2,400 A and 400 B; (2,400 × 2) + (400 × 3) | 2,800 units; 6,000 hours |
| Actual output in units and standard hours | 2,200 A and 300 B; (2,200 × 2) + (300 × 3) | 2,500 units; 5,300 hours |
| Standard fixed overhead rate | $120,000 ÷ 6,000 budgeted hours | $20 per standard hour |
| Fixed overhead applied to actual output | 5,300 standard hours × $20 | $106,000 |
| Production volume variance | $120,000 budgeted − $106,000 applied | $14,000 unfavorable |
| Fixed overhead spending variance | $116,000 incurred − $120,000 budgeted | $4,000 favorable |
| Fixed overhead underapplied | $116,000 incurred − $106,000 applied | $10,000 underapplied |
The plant missed the original output plan by 300 units. The 700-hour gap between budgeted and standard hours drove $14,000 of unfavorable volume variance. The $4,000 favorable spending variance offset part of that gap, leaving $10,000 of fixed overhead underapplied. The reconciliation explains the relationship among incurred, budgeted, and applied amounts. It does not describe when cash was paid.
Suppose the machines logged 5,700 actual hours. Using that reading would apply $114,000 and shrink the reported volume variance to $6,000, even though the plant made the same parts. Keep those clock hours for a capacity or efficiency analysis. For the volume calculation, use the hours the actual finished units earned under the standard.
Keep the plan, standard, and ledger on separate rows
Save the original budget version, activity denominator, cost-center scope, rate, and effective date. Keep the dated product standards and map completions and reversals to their products and operations. If a product has two standards after a routing change, match each completion to the approved effective version so a later edit does not recalculate prior output at today’s hours.
Show actual fixed overhead incurred as a separate ledger input. OpenStax’s overhead variance chapter distinguishes fixed and variable overhead calculations. Keep variable spending and usage on their own lines. A higher power bill for running a machine can need investigation without explaining the fixed volume variance.
Read the unit gap alongside the hour gap. If you replace one hundred units of A with one hundred units of B in the example, output count stays the same and standard hours increase by one hundred. At the same rate the plant applies another $2,000. That is a mix effect under this rate. The manufacturing capacity planning article covers the separate question of what load the work centers can take next.
Have the production lead confirm missing completions and the cost owner verify that the fixed budget and ledger use the same scope. Use Total manufacturing cost formula when you need to follow the larger cost flow across materials, labor, overhead, and inventory.
Inspect a month’s production data
Start with a supported source to check whether completion records retain the product and cost-center fields needed for the comparison.
Where Permute fits in the variance review
Permute is the context layer we sell between operating records and the AI tools people use. We can connect supported ERP and planning sources and match completions, production standards, and approved budgets by plant, cost center, period, and product.
We can put the declared sign and denominator rules into a repeatable report. The plant controller can then trace applied overhead back to the completion records and approved rate, with missing standards visible before the total is finalized.
A cost-center owner can ask which products changed the standard hours behind their variance and see the output records and rule versions they’re permitted to access.
Keep accounting policy and postings with the controller
We read connected systems and do not write back into the system of record or choose the activity base, inventory treatment, or journal entries. The controller approves those choices under the business’s accounting policy and applicable reporting requirements.
Reconcile output and spending before assigning a cause
Production volume variance isolates the fixed overhead effect of actual output at the approved standard rate. Preserve the denominator and sign convention so the next reviewer can reproduce the amount. In the example, lower output produces a $14,000 unfavorable volume variance while lower fixed spending offsets $4,000. The plant can use the two amounts to investigate output and spending separately.
Review a plant’s overhead report with Permute
Bring the approved rate, the completions behind one month, and the budget version used in the variance.
Questions about fixed overhead volume variance
Can volume variance be zero when spending is over budget?
Yes. Output can absorb exactly the budgeted fixed overhead even when the plant incurs a higher amount. The difference then appears in the fixed overhead spending variance.
Why does my report show an unfavorable variance as a negative number?
Some reports subtract the budget from the applied amount. That flips the sign used here and leaves the favorable or unfavorable label the same when the convention is applied consistently.
What if a completed product has no approved standard?
Flag the missing rate basis and show which output is affected. Ask the cost owner to confirm the applicable standard before treating the applied total as complete.