Manufacturing Overhead Allocation

Jul 24, 2025

Overview

This lecture explains why manufacturing overhead is sometimes over- or under-allocated and how better estimation of allocation bases improves accuracy.

Overhead Allocation Concepts

  • Manufacturing overhead is allocated to jobs at the start of the year using estimated data.
  • A predetermined overhead allocation rate is used, often based on expected costs and allocation bases like direct labor hours.
  • Actual outcomes can differ from estimates, causing over- or under-allocation.

Examples of Over/Under Allocation

  • An under-costed job (skinny widget) results when overhead is underestimated.
  • An over-costed job (fat widget) occurs when overhead is overestimated.

Improving Allocation Accuracy

  • Analyzing main cost drivers, such as labor hours, machine hours, or a combination, can improve overhead estimates.
  • Selecting the most relevant allocation base helps the cost accountant match overhead costs more closely to actual production.

Key Terms & Definitions

  • Manufacturing Overhead — Indirect production costs not directly traceable to a specific product.
  • Allocation Base — A measure (e.g., direct labor hours, machine hours) used to assign overhead costs to products or jobs.
  • Predetermined Overhead Rate — Estimated overhead cost divided by estimated allocation base at the year's start.
  • Over-allocated Overhead — When assigned overhead exceeds actual overhead incurred.
  • Under-allocated Overhead — When assigned overhead is less than actual overhead incurred.

Action Items / Next Steps

  • Review the methods for selecting allocation bases in your textbook.
  • Practice problems on calculating and adjusting for over- and under-allocated overhead.