Overhead Absorption
What is the difference between overhead absorption and overhead allocation?
Allocation places indirect costs into cost pools or cost centers; absorption charges those pooled costs into products, jobs, or receipts using a predetermined rate or rule.
What is the standard formula for an overhead absorption rate?
The common formula is total overhead cost divided by the chosen allocation base, such as labor hours, machine hours, units, or material cost.
What happens when applied overhead exceeds or falls below actual overhead?
Over-absorption occurs when applied overhead exceeds actual overhead, creating a favorable variance and possibly overstating product cost recovery. Under-absorption occurs when applied overhead is below actual overhead, creating an unfavorable variance and leaving overhead unrecovered in product costing.
Overhead absorption is the process of assigning indirect manufacturing or supply-chain costs—such as indirect labor, utilities, maintenance, depreciation, and quality—to a cost object like a product, batch, work order, or receipt transaction. It typically applies a predetermined absorption rate or a fixed/percentage rule so inventory valuation and cost of goods sold include factory burden.
In a real manufacturing environment, overhead absorption is executed during cost rollup, standard-cost update, or receipt posting. A rate base is selected—machine hours, labor hours, units, or material cost—and the burden is pushed into WIP completions, backflushed components, or purchase order receipts. This makes finished goods and subassemblies carry plant support costs instead of only direct material and labor. In receiving, absorption rules control whether overhead hits at PO receipt, transfer, or miscellaneous receipt, which affects inventory valuation timing and prevents internal moves from inflating cost. On the shop floor, percentage-based absorption layers overhead onto material cost, which matters for high-value inputs, energy-intensive processes, and outsourced operations. The practical goal is to make the burden rate reflect expected capacity so standard costs remain stable for pricing, margin analysis, and variance control.
Low-volume under-absorption: A plant running below budgeted activity still incurs fixed utilities, supervision, and depreciation, so actual overhead exceeds applied overhead. Unit cost spikes and period-end variance clearance reveals under-recovered burden, distorting inventory and margin reporting.
Wrong-transaction absorption: Applying overhead to miscellaneous receipts or subinventory transfers when it should only hit PO receipts or production completions double-counts burden. Internal moves are not economic acquisitions, so transfers inflate WIP-to-finished-goods value artificially.
Inappropriate absorption base: Spreading overhead by material cost when consumption is machine-hour driven overburdens high-value, low-processing items and underburdens labor-intensive ones. That mismatch distorts product costing, make-or-buy decisions, and SKU margin rankings.