Over- and Under-Applied Overhead

When a firm applies overhead to jobs using a predetermined rate, it inevitably overshoots or undershoots the actual overhead incurred. This variance—the difference between applied (budgeted) overhead and actual overhead—must be analysed and closed to cost of goods sold, revealing whether the rate was accurate.

How the variance arises

Throughout a period, a firm applies overhead to jobs using a predetermined rate—say, $12 per machine hour. Each job is charged that standard amount, and work-in-process inventory accumulates these applied costs. But when the period closes, the accountant tallies the actual overhead paid: rent, utilities, salaries, depreciation, insurance. If production ran 10,000 machine hours and the rate was $12/hour, $120,000 was applied. Yet actual overhead might have been $115,000 (underapplied) or $130,000 (overapplied).

The gap arises from two sources. First, activity forecasts might be wrong. If the firm predicted 10,000 machine hours but ran only 9,000, less overhead was applied even if the rate itself was accurate. Second, the budgeted overhead cost might be wrong—a surprise utility bill, an emergency repair, or a bonus paid that was not foreseen drives actual overhead above budget.

Overapplied overhead

Overapplication occurs when applied overhead exceeds actual overhead. For example, if $120,000 was applied but only $110,000 was actually spent, the variance is $10,000 overapplied. This signals that either the firm was more efficient than expected, predicted activity too high, or both costs and activity were better than forecast. The journal entry reverses part of the overhead charged to work-in-process.

In economic terms, the goods produced are “overcosted” using the predetermined rate. If these goods have already been sold, reporting the overapplication as a credit reduces cost of goods sold and boosts profit. If goods remain in inventory, the decision is whether to adjust inventory balances or flow the variance through profit-and-loss.

Underapplied overhead

Underapplication happens when actual overhead exceeds applied overhead. If $110,000 was applied but $120,000 was actually incurred, the variance is $10,000 underapplied. Possible causes: the firm ran more machine hours than predicted (more activity than forecast), overhead costs overran budget, or both. The journal entry supplements work-in-process and eventually cost of goods sold with the shortfall.

The goods are undercosted relative to true overhead consumption. If sold, this variance reduces reported profit; if still in inventory, it increases the balance-sheet carrying value.

Closing the variance

Most firms close the variance to cost of goods sold at period-end. The logic is pragmatic: overhead is an indirect cost that becomes part of the cost of goods sold eventually. If goods are still in inventory, they will be sold (or written off) in a future period, at which point the variance will travel with them. Closing all variance to COGS in the current period simplifies the ledger and reflects the realisation that applied overhead is always an estimate.

However, if the variance is large relative to inventory balances, some firms prorate it among inventory, work-in-process, and COGS, ensuring that ending inventory is valued closer to true overhead. This is more precise but more tedious.

Analysing the variance

Breaking down the overall variance into components reveals root causes. Most accounting systems separate:

• Spending variance: Did actual overhead cost match the budget? If actual overhead was $120,000 but budgeted was $110,000, there’s a $10,000 unfavourable spending variance.
• Volume variance: Did actual activity match forecast? If 9,000 machine hours were predicted but 10,000 occurred, more overhead was applied due to higher volume, creating a favourable volume variance (more fixed costs were absorbed across more output).

A firm might have an unfavourable spending variance offset by a favourable volume variance, yielding a small net variance. This decomposition helps management decide whether to adjust next period’s budget or rate.

Materiality and thresholds

Firms rarely fuss over a $500 variance on a $100,000 overhead base. They set materiality thresholds—variances below 5 per cent or a dollar threshold might be ignored, while larger variances trigger investigation. This reduces noise and focuses attention on significant deviations.

Standard costing and variance interpretation

Under standard costing, variance analysis goes deeper. Instead of a single applied-versus-actual figure, the firm calculates overhead spending variance, volume variance, and sometimes efficiency variance (how many standard hours of activity should have been consumed versus actual activity). These tell a richer story: Was the overhead budget realistic? Did the production process run efficiently relative to standard? Did unexpected events (machine breakdown, supplier delay) distort results?

Practical complications

In real firms, establishing “actual overhead” is itself tricky. Some costs—like depreciation—are accruals that must be estimated. Shared costs (e.g., the plant manager’s salary split across departments) require allocation logic. And if the firm uses multiple predetermined rates across departments, each generates its own variance, requiring careful reconciliation.

Also, the choice of activity base matters. If the predetermined rate uses labour hours but actual activity is tracked in machine hours, mismatches create persistent variance. Data systems must align.

Continuous variance monitoring

Modern firms do not wait until period-end to spot huge variances. Monthly dashboards show applied versus actual overhead, flagging trends. If a consistent underapplication emerges mid-year, management can adjust next period’s rate forecast or investigate why actual costs are running hot. This early-warning approach prevents surprises and supports continuous improvement.

See also