Plain definition
Mixed costs contain a fixed component and a component that varies with activity. A utility bill may include a standing charge plus usage; treating the entire bill as fixed or variable distorts forecasts and decisions.
Illustrative example
Monetary examples use Saudi riyals (SAR). The same principles apply in other currencies.
A warehouse electricity bill is standing charge plus per pallet moved. At 3,000 pallets it is . When operations proposes 1,000 extra pallets, finance adds usage, not the full , but also checks whether the higher activity needs extra equipment.
Why it matters
The split matters because contribution and cash forecasts need to show what changes with the decision and what remains committed.
Practical consequence
Use contracts, meter data, or a credible activity analysis to estimate both components. Revisit the split when tariffs, capacity, or the driver changes.