# Marginal Costing: Characteristics, Comparison, and Applications
## What is Marginal Costing?
A costing technique where only variable (marginal) costs are treated as product costs. Fixed costs are written off entirely to the Profit & Loss account as period costs in the period incurred.
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## Characteristics of Marginal Costing
1. All costs classified as fixed or variable only — no semi-variable category
2. Variable costs = product costs (carried forward in inventory)
3. Fixed costs = period costs (charged to P&L immediately; not in inventory)
4. Finished goods and WIP valued at marginal (variable) cost only
5. Prices set with reference to marginal cost and contribution margin
6. Products and departments ranked by contribution margin, not net profit
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## Marginal Costing vs. Absorption Costing
| Aspect | Marginal Costing | Absorption Costing |
|---|---|---|
| Fixed cost treatment | Period cost → P&L | Product cost → inventory |
| Inventory valuation | Variable cost only | Variable + Fixed cost |
| Cost data focus | Highlights contribution | Highlights profit per product |
| Cost per unit | Constant regardless of volume | Decreases as volume rises (FC per unit falls) |
| Profitability measure | P/V Ratio | Profit after FC apportionment |
Profit difference between the two systems:
- When production > sales: Absorption profit > Marginal profit (FC deferred in closing stock)
- When production < sales: Absorption profit < Marginal profit (past FC released from opening stock)
- When production = sales: Both give the same profit
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## Advantages of Marginal Costing
1. Simplified pricing — VC per unit is constant, FC is constant in total; no complex apportionment
2. Proper overhead recovery — avoids over/under-absorption that occurs under absorption costing
3. Realistic profit — no fixed cost deferred in unsold stock; profit reflects actual sales performance
4. Production level decisions — BEP analysis shows exact impact of volume changes on profit
5. Better cost control — actual variable expenses compared directly against budget
6. Aids decision making — make-or-buy, shut down or continue, accept special orders
7. Short-term profit planning — BEP and contribution analysis form the foundation
## Limitations of Marginal Costing
1. Classification difficulty — most costs are semi-variable; splitting into fixed and variable is subjective
2. Key factor dependence — high contribution alone does not ensure optimum profit without linking to the limiting resource
3. Risk of under-pricing — sales staff may treat marginal cost as total cost and price too low
4. Faulty WIP valuation — large contracts (e.g., contract costing) should include fixed OH in WIP
5. Cost unpredictability — fixed costs are not truly fixed (salaries rise with increments); variable costs are not truly constant (raw material prices fluctuate)
6. Ignores time and investment — two jobs with the same marginal cost may require very different completion times
7. Understates WIP — WIP is valued lower, which may not represent true economic value
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## Practical Applications
1. Pricing Policy — floor price for special orders = variable cost (any price above VC contributes to FC recovery)
2. Decision Making — make-or-buy, shut-down vs. continue, product mix selection
3. Realistic Profit Ascertainment — no distortion from FC deferral in inventory
4. Determining Production Level — BEP shows minimum volume; contribution analysis shows optimal volume
5. Shut-down Decision — continue operations as long as sales revenue ≥ variable costs + avoidable fixed costs