Cost Accounting Made Practical

From costing methods to decision-making—learn what matters and how to apply it.

Introduction

Cost accounting is not just about calculating costs—it’s about making better decisions: pricing, profitability, and efficiency. Once you understand the key categories, the calculations become predictable.

1) Understand cost behavior

• Fixed costs: don’t change with volume (rent)

• Variable costs: change with volume (materials)

• Mixed costs: part fixed, part variable

2) Product vs Period costs

• Product costs: inventory-related (COGS)

• Period costs: expensed in the period (selling/admin)

3) Job Order vs Process costing

• Job order: unique jobs (custom furniture)

• Process: mass production (cement, beverages)

4) Cost-Volume-Profit (CVP) analysis

This is one of the most useful tools.

Key ideas:

• Contribution Margin = Sales – Variable Costs

• Break-even = Fixed Costs / Contribution Margin Ratio

5) Relevant costing for decisions

Ignore sunk costs. Focus on future differences:

• Make or buy

• Special orders

• Drop a product line

• Constraints (limiting factor decisions)

Practical habit

After any calculation, ask:
What decision does this support?