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Support Department Cost Allocation: A Step-by-Step Example

A support department cost allocation example demonstrates how indirect costs—IT, HR, facilities—flow into product lines using two competing methods: the direct method (simple, ignores interdepartmental services) and the step-down method (sequential, captures partial service sharing). Walking through the numbers shows why choice of method matters for product profitability.

The Scenario

Imagine a small manufacturer with three support departments and two production departments:

DepartmentAnnual Cost
IT$200,000
HR$150,000
Facilities$100,000
Production A$500,000 (direct labor + materials)
Production B$400,000 (direct labor + materials)

The company produces two products: Product X (made in both departments) and Product Y (made in Production A only).

To calculate the true cost of each product, the support department costs must be allocated to Production A and Production B. But how?

First, identify the allocation drivers:

  • IT support is consumed based on number of users and computing power. Let us use “headcount” as the driver.
  • HR support is consumed based on number of employees to recruit, train, and administer.
  • Facilities is consumed based on square footage occupied.

The company has the following data:

IT UsersEmployeesSq. Footage
IT Dept582,000
HR Dept351,500
Facilities Dept231,000
Production A306015,000
Production B153010,000
Total5510629,500

The Direct Method

Under the direct method, support department costs are allocated only to the production departments. Any services that support departments provide to each other are ignored.

Calculate the allocation rates for each support department, using only the production departments as the denominator:

IT allocation rate:

  • IT users in production depts only: Production A (30) + Production B (15) = 45
  • Allocation rate: $200,000 ÷ 45 = $4,444.44 per IT user

HR allocation rate:

  • Employees in production depts only: Production A (60) + Production B (30) = 90
  • Allocation rate: $150,000 ÷ 90 = $1,666.67 per employee

Facilities allocation rate:

  • Sq. footage in production depts only: Production A (15,000) + Production B (10,000) = 25,000
  • Allocation rate: $100,000 ÷ 25,000 = $4.00 per sq. foot

Now allocate each support cost:

DepartmentIT Cost AllocatedHR Cost AllocatedFacilities Cost AllocatedTotal Allocated
Production A30 × $4,444.44 = $133,33360 × $1,666.67 = $100,00015,000 × $4.00 = $60,000$293,333
Production B15 × $4,444.44 = $66,66730 × $1,666.67 = $50,00010,000 × $4.00 = $40,000$156,667
Total Allocated$200,000$150,000$100,000$450,000

Total cost after allocation:

  • Production A: $500,000 + $293,333 = $793,333
  • Production B: $400,000 + $156,667 = $556,667

The direct method is fast and transparent. But it ignores that IT provides 5 users to the IT department itself, HR manages the HR department, and Facilities occupies 1,000 sq. ft. Those internal costs are absorbed by the production departments and effectively shifted proportionally to them. Many accountants consider this imprecise.

The Step-Down Method

The step-down method recognizes that support departments serve each other. The usual order is:

  1. Facilities (consumes the fewest services from other depts)
  2. IT (consumes Facilities, provides to HR and Production)
  3. HR (provides to Production)
  4. Production depts (consume the others)

Step 1: Allocate Facilities

Facilities costs are allocated to all other departments (IT, HR, Production A, Production B), using the full headcount (including Facilities’ own staff):

  • Allocation rate: $100,000 ÷ 29,500 sq. ft. = $3.39 per sq. foot
DepartmentAllocation
IT Dept2,000 × $3.39 = $6,780
HR Dept1,500 × $3.39 = $5,085
Production A15,000 × $3.39 = $50,850
Production B10,000 × $3.39 = $33,900
Total$100,000

Step 2: Allocate IT (now includes Facilities allocation)

IT’s new total: $200,000 + $6,780 = $206,780

IT is allocated to HR, Production A, and Production B (not back to Facilities, which has already been allocated):

  • IT users excluding IT dept itself: HR (3) + Production A (30) + Production B (15) = 48
  • Allocation rate: $206,780 ÷ 48 = $4,307.50 per user
DepartmentAllocation
HR Dept3 × $4,307.50 = $12,922.50
Production A30 × $4,307.50 = $129,225
Production B15 × $4,307.50 = $64,612.50
Total$206,780

Step 3: Allocate HR (now includes Facilities and IT allocations)

HR’s new total: $150,000 + $5,085 + $12,922.50 = $168,007.50

HR is allocated to Production A and Production B:

  • Employees in HR (excluding HR itself): Production A (60) + Production B (30) = 90
  • Allocation rate: $168,007.50 ÷ 90 = $1,866.75 per employee
DepartmentAllocation
Production A60 × $1,866.75 = $112,005
Production B30 × $1,866.75 = $56,002.50
Total$168,007.50

Step 4: Total Allocated Costs

DepartmentOriginal CostFacilitiesITHRTotal
Production A$500,000$50,850$129,225$112,005$792,080
Production B$400,000$33,900$64,612.50$56,002.50$554,515
Total$900,000$100,000$206,780$168,007.50$1,346,595

Comparison

MetricDirect MethodStep-Down Method
Production A Total Cost$793,333$792,080
Production B Total Cost$556,667$554,515
Difference—$1,253 shift to A, $2,152 shift to B

In this example, the difference is small (< 1%). In larger firms with heavier interdepartmental service sharing, step-down allocations can shift product costs by 5–15%, materially changing which products appear profitable.

Why the Method Matters

If the company uses the direct method and Product X has a unit cost of $100, but the step-down method yields $103, the difference might determine whether a pricing decision or a make-or-buy decision is sound. Accountants and cost managers must choose a method and apply it consistently, disclosing the choice in footnotes.

The step-down method is a practical middle ground: more realistic than direct allocation, but far simpler than the reciprocal method (which requires solving simultaneous equations and is rarely used outside textbooks).

See also

Wider context