Why a purchasing price variance does not equal the production cost variance

A purchasing report may measure a price difference on all material bought, while a production report measures cost for material consumed. When some purchases remain in stock, those populations differ. Adding the purchasing price variance to a production usage variance will not automatically reconcile to the cost of the output produced.

Label whether each price measure applies to purchased, received, invoiced or consumed quantity. Also retain the standard price version and the cost components included in actual price. A favorable or adverse label is incomplete without the quantity and valuation basis behind it.

ACCA's performance-management examples use quantity purchased for purchasing price comparisons, while its materials-variance guidance compares actual usage with the standard quantity allowed for actual output. The following worksheet bridges those ideas using one material lot. It is an analytical reconciliation; accounting entries and inventory valuation follow the business's applicable policy.

Suppose the standard price is $10 per kilogram. The company purchases 1,000 kilograms at $11, for $11,000. Comparing the same purchased quantity at standard and actual prices gives a $1,000 adverse purchase-price difference: 1,000 multiplied by $1.

During the period, production consumes 600 kilograms from that lot and leaves 400 kilograms unused. Assume no opening stock, returns, losses outside production or other price components, so the quantity and cost bridge is deliberately simple. The actual cost associated with the consumed material is $6,600, while the remaining purchased material carries $4,400 of actual acquisition cost in this analytical view.

At the standard price, those two portions are $6,000 and $4,000. The purchase-price difference divides into $600 associated with consumption and $400 associated with material still held. The total remains $1,000. The unused portion explains why the purchase-based number is larger than the price effect on this period's material use.

Assume actual output was 110 finished units and the standard allows 5 kilograms per finished unit. Standard material allowed is therefore 550 kilograms. The operation used 600 kilograms, an excess of 50 kilograms. Valued at the $10 standard price, the usage variance is $500 adverse.

The standard material cost allowed for actual output is $5,500. Actual consumed cost is $6,600, so the total consumption-cost difference is $1,100 adverse. That reconciles to $600 of price effect on the consumed quantity plus $500 of usage effect.

Adding the $1,000 purchase-price difference to the $500 usage difference gives $1,500, which is $400 too high for this consumption comparison. That $400 belongs to the price difference associated with the unused stock. It is not an unexplained production inefficiency or a reason to force a balancing journal.

Supplier credits received after purchase require a defined reporting cutoff. A later rebate may change the acquisition-price comparison without changing kilograms consumed. Preserve the original variance and show the credit's effect as a revision or current-period adjustment under the approved reporting policy. Otherwise purchasing can appear to improve just because a previously earned credit arrived, while production's material-use report remains unchanged.

Reconcile opening stock, receipts, issues, returns and closing stock in physical units. A missing material return can make usage look excessive. A late receipt can put its invoice price in one period and its quantity in another. Resolve those timing and completeness issues before treating the variance as evidence about a team's performance.

With several purchase lots, identify the cost-flow and analytical convention used to connect prices to consumed material. The simple $11 rate above applies because all material comes from one lot. A last-purchase price may be unsuitable when production consumed older stock at different acquisition costs.

Keep standard changes separate from actual price changes. If the standard moves from $10 to $10.50 during the period, a comparison using mixed versions can create a variance simply through the reference update. Freeze or explicitly bridge the standard version used for each report.

A lower purchase price may accompany poorer material quality, additional waste or rework. Conversely, a higher-priced input may improve yield. The two variance measures help locate the changes, but neither proves the supplier caused them. Inspect specifications, quality results, handling and production conditions before assigning responsibility.

The allowed quantity must reflect actual finished output on a consistent basis. Including unfinished or rejected units as accepted output can reduce the apparent usage variance without improving the process. Preserve work-in-progress and quality classifications so the comparison reflects what was actually produced.

Separate abnormal events that need their own explanation. Trial runs, engineering changes and an approved material substitution may have different expected usage from routine production. Keep their cost in the accounts while providing an analytical view that shows the event and the continuing process distinctly.

Purchasing needs the price result on the quantity it committed to or bought. Operations needs the quantity and price effects relevant to the material consumed for its output. Finance needs the stock and ledger reconciliation. Keep those views linked by the physical flow instead of forcing all teams to use a single variance total for different purposes.

The treatment of price variances in statutory inventory and profit can depend on the accounting framework, costing system and materiality. Have the accounting owner confirm that treatment. The $400 stock-associated difference in this example is an explanation of the analytical populations, not an instruction to capitalize or expense it automatically.

Publish the standard version, quantity basis, price components and inventory bridge with the result. A useful explanation can then be precise: the purchase price was $1 per kilogram above standard, $600 of that effect related to material consumed, and production used 50 kilograms more than allowed for actual output. The remaining $400 is traceable to unused purchased material.