Dictionary / Opportunity Cost
What does Opportunity Cost mean in accounting?
Quick definition
GeneralProspective change in cost following the adoption of an alternative machine, process, raw material, specification, or operation. This term guides how bookkeepers record, classify, and explain related transactions in routine financial reporting.
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Examples
A new dryer vs the old one
You run a screen-printing shop, and your 2014 conveyor dryer still runs. On June 11 a press supplier quotes a new electric dryer at $8,400. The old dryer burns about $180 more electricity each month plus $90 in reprints from uneven heat, so adopting the new dryer would drop operating cost $270 a month; that $270 is the opportunity cost of staying with the old machine, the cost you give up by not switching. Use $270 a month against the $8,400 quote when you decide whether to switch. If you buy, that supplier's bill posts to fixed assets; the comparison itself does not.
Do not journal the ply you skipped
You run a joinery shop. In early October you compare 3/4-inch Baltic birch from a plywood supplier at $54 a sheet with maple ply from a maple supplier at $69; switching the spec would raise material cost $15 a sheet, or $600 on a 40-sheet run. That $600 is the opportunity cost of adopting maple: the prospective cost change if you change raw material. You switch for the look and enter the maple supplier's bill at $2,760 to job materials or inventory. Do not add a journal entry dated October 8 that debits Opportunity cost $600 and credits materials or income; QuickBooks Online and Xero should show only the sheets you bought.
Why it matters
Opportunity cost is the forward-looking change in cost if you adopt a different machine, process, raw material, specification, or operation. You compute it when you compare those alternatives, not at every month-end close, and you will not post an account with this name. Mix it with incremental cost and you treat the extra outlay of one more unit as the cost you give up by picking one setup over another. Journal the figure, or fold in money already spent on the old setup, and you invent a cost the bank never saw; leave the comparison on the decision worksheet and post only what you actually buy.
Further reading
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What is Opportunity Cost in bookkeeping?
Prospective change in cost following the adoption of an alternative machine, process, raw material, specification, or operation.
When should I use Opportunity Cost?
Use Opportunity Cost when the transaction facts match its definition and you need the ledger and financial statements to reflect the correct account and period.
What is a common mistake with Opportunity Cost?
Opportunity Cost is used for opportunity cost entries, while Offset covers a related but distinct bookkeeping purpose. Review both terms before posting unusual transactions. A common mistake is applying it by label only instead of checking the underlying transaction details.