Cost Analysis — Formula Cheat Sheet

Modules 7–10 (ABC, Pricing, Master Budget, CVP) — final exam quick reference


Module 7 — Activity-Based Costing

Pool rate (predetermined overhead rate for each activity cost pool):

Pool rate = Budgeted overhead in pool ÷ Budgeted total cost-driver quantity

(Always divide by the total driver quantity across all products — never by each product's quantity separately. There is only one pool of money, so only one rate.)

Overhead allocated to a product (per pool):

Allocated overhead = Pool rate × Quantity of cost driver consumed by that product

Total overhead allocated to a product (across all pools):

Total overhead = Σ (Pool rate × Cost driver consumed) over all pools

Total product cost (manufacturing cost per unit):

Total cost = Direct materials + Direct labour + Σ Allocated overhead

(If the question asks for overhead only, stop after Σ allocated overhead. If it asks for product cost or manufacturing cost per unit, you MUST add DM and DL. Don't lose marks by forgetting this.)

Four-level cost hierarchy — match driver to level:

LevelDriver examples
Unit-levelUnits, machine hours, direct labour hours
Batch-levelNumber of setups, orders, inspections, batches
Product-sustainingNumber of products, engineering changes, design hours
Facility-sustainingSquare metres (often allocated arbitrarily)

Module 8 — Pricing

Target Costing (market-based, used in competitive markets):

Target Cost = Target Price − Target Operating Income per unit

(Price is given by the market; gap to current cost is closed by value engineering.)

Cost-Plus Pricing (used in non-competitive markets):

Price = Cost base × (1 + Markup %)
Price = Cost base + Markup $ per unit

Markup % from a target return on investment:

Target annual operating income = Investor capital × Target ROI
Target operating income per unit = Annual target OI ÷ Units sold
Markup % = Target OI per unit ÷ Cost base per unit

Cost-base options (largest base ↔ smallest markup needed):

Cost baseIncludes
Variable manufacturingDM + DL + Variable MOH
VariableVariable manufacturing + Variable period
Manufacturing (absorption)DM + DL + All MOH
Full cost (preferred in long-run pricing)All manufacturing + all period costs

Cost incurrence vs locked-in costs: Most cost is locked in at the design stage, long before it is incurred. Reduce cost before lock-in — afterwards is too late.


Module 9 — Master Budget

Golden rule of budget sequencing: the first line of any sub-budget = the last line of the previous sub-budget.

Sequence (operating budget):
Revenue → Production → Materials usage → Materials purchases → Direct labour → MOH → Ending inventories → COGS → Operating expenses → Budgeted income statement.

Revenue (Sales) Budget:

Revenue = Selling price × Units sold (per product)

Production Budget (units):

Sales units (from revenue budget)
+ Target ending finished-goods inventory
− Beginning finished-goods inventory
= Units to produce

Materials Usage Budget (per material):

Material quantity used = Units to produce × Quantity of material per unit of product
(Sum across products to get total usage of each material. No inventory adjustment here.)

Materials Purchases Budget (per material):

Material needed for production
+ Target ending raw-material inventory
− Beginning raw-material inventory
= Materials to purchase (in units)
× Cost per unit of material = Total purchase cost

Direct Labour Budget:

Labour cost = Units to produce × Labour hours per unit × Wage rate per hour
(Separate calculation per labour type, then sum. No inventory.)

MOH Budget: Variable MOH = rate × driver; Fixed MOH = total.

COGS Budget: DM used + DL + MOH + Beginning FG inventory − Ending FG inventory.

Budgeted Income Statement:

Revenue − COGS = Gross margin − Operating expenses = Operating income

Cash Budget (build via two supporting schedules, then assemble month-by-month)

Schedule (a) — Receipts: For each month, collect from sales using collection terms (e.g., 60% in month of sale, 25% next month, 15% month after). Go back enough months to cover the collection tail. Add one-off cash inflows.

Schedule (b) — Disbursements:

Cash Budget (run one month at a time, in order):

Opening cash balance
+ Total receipts (from schedule a)
= Cash available
− Total disbursements (from schedule b)
= Ending cash balance → this becomes next month's opening balance

(You cannot do all months in parallel — each opening balance depends on the previous closing balance.)

Cash-position levers: collect faster; pay slower; invest idle cash short-term.


Responsibility centres

CentreManager controls
Cost centreCosts
Revenue centreRevenues (theoretical only — can't exist without cost responsibility too)
Profit centreRevenues + Costs
Investment centreRevenues + Costs + Investment decisions

Module 10 — CVP Analysis

Core definitions:

Contribution Margin per unit (CMU) = Selling price − Variable cost per unit
Total Contribution Margin = Revenue − Total variable cost
Contribution Margin Ratio (CMR) = CM ÷ Revenue = CMU ÷ SP
Operating Income = Total CM − Total Fixed Cost

The one CVP formula to memorise (target-OI form; break-even is just target = 0):

Units = (Fixed cost + Target operating income) ÷ Contribution margin per unit
Revenue $ = (Fixed cost + Target operating income) ÷ Contribution margin ratio

Break-even (set Target OI = 0):

Break-even units = Fixed cost ÷ CMU
Break-even revenue = Fixed cost ÷ CMR

Income taxes — convert target to pre-tax first:

Pre-tax target OI = Net income ÷ (1 − Tax rate)
Then plug into the target-OI formula above.

(Tax does NOT affect break-even — at break-even, profit = 0, so there is no tax to pay.)

Margin of safety:

Margin of safety ($) = Budgeted revenue − Break-even revenue
Margin of safety (units) = Budgeted units − Break-even units
Margin of safety (%) = Margin of safety $ ÷ Budgeted revenue

Degree of operating leverage (DOL):

DOL = Contribution margin ÷ Operating income (at a given activity)
% change in operating income = DOL × % change in sales

(High DOL = more fixed cost relative to variable = bigger upside AND downside per 1% revenue change.)


Multi-product CVP (sales-mix held constant)

Weighted-Average Unit CM (WAUCM) = Σ (CM per unit × Sales mix proportion)
Total break-even units = Fixed cost ÷ WAUCM
Then split back into individual products: each product's break-even units = Total break-even units × that product's mix proportion

(Never report only the total — split it back, otherwise the answer is meaningless.)


CVP assumptions (be ready to list)

  1. Sales volume is the only driver of cost and revenue changes.
  2. Total cost is divisible into fixed and variable components.
  3. Cost and revenue functions are linear within the relevant range.
  4. Selling price, variable cost per unit, and fixed cost are known and constant.
  5. Single product, OR sales mix is known and constant.
  6. All units produced are sold (no inventory build).
  7. Time value of money ignored (CVP is short-term).

Round-up rule

CVP units always round UP — never down. 231.2 → 232. (At 231 you have not actually broken even.)


Exam-day reminders