Managerial — Excel guide
Inward-facing accounting: how costs behave, where breakeven sits, and which costs should (and shouldn't) drive decisions.
Cost behavior & contribution margin
Fixed costs don't move with volume (rent); variable costs do (materials). Contribution margin = price − variable cost per unit: what each sale contributes toward fixed costs, then profit.
Costs that fool decision-makers
SUNK costs are spent and unrecoverable — irrelevant to what happens next, however painful. OPPORTUNITY cost is the value of the best alternative you give up — invisible on statements, central to decisions.
Variance analysis
Actual vs budget, split into price and quantity effects: did we pay more per unit, or use more units? Favorable/unfavorable labels beat raw differences because they carry direction.
Capital budgeting bridges
Payback period is the quick risk screen; NPV and IRR are the real decision tools — see the NPV & IRR cheat sheet on the finance side. WACC is the discount rate a company's NPVs should clear.