Unit costing is a method of working out the cost of producing one unit of output by dividing the total cost incurred during a period by the number of units produced. Also known as single-output costing, it is used by businesses that manufacture one standardised product on a continuous basis, such as brick kilns, sugar mills, cement plants and mining operations.
The method relies on a cost sheet, a structured statement that separates material, labour and overhead costs, so a business can see where its money goes and how a saving on one unit adds up when multiplied across thousands of units.
How does a unit cost sheet work
A cost sheet arranges expenses into stages, with each stage adding a cost category to the one before it, as shown below.
|
Cost head |
What it covers |
|
Prime cost |
Direct material used, direct labour and direct expenses on the product |
|
Works cost |
Prime cost plus factory overheads such as power, supervision and depreciation on plant |
|
Cost of production |
Works cost plus administration overheads, adjusted for opening and closing stock of finished goods |
|
Cost of goods sold |
Cost of production adjusted for finished goods stock held during the period |
|
Cost of sales |
Cost of goods sold plus selling and distribution overheads, such as freight and sales commission |
|
Cost per unit |
Cost of sales divided by the number of units produced during the period |
Reading down the sheet shows how a rupee spent on raw materials eventually becomes part of the final selling price once factory, administrative and selling costs are added.
How do you calculate cost per unit?
Cost per unit is the cost of sales for a period divided by the number of units produced in that period. A cement plant that spends ₹42,00,000 to produce 60,000 bags of cement in a month arrives at a cost per unit of ₹70 per bag. Comparing this figure month on month, or against a target cost, shows whether a rise in material prices or a fall in output is pushing up the cost of each unit.
What costs go into a unit cost sheet
A cost sheet groups expenses under a few standard heads before they are added up.
- Direct material is the raw material that becomes part of the finished product
- Direct labour, wages paid to workers directly engaged in production
- Direct expenses, costs tied to a specific job or product, such as royalty or hire of special equipment
- Factory overheads, indirect costs of running the plant, such as power, supervision and depreciation
- Administration overheads, office and management expenses not tied to production
- Selling and distribution overheads, costs of getting the product to the customer, such as freight and sales commission
How is unit costing different from job costing and process costing
Job costing tracks the cost of each order separately, which suits a business making custom furniture or printing, where every job differs from the last. Process costing follows a product through several distinct stages, such as a textile mill that spins, dyes and weaves cloth in separate departments and calculates a cost for each process before arriving at a final figure.
Unit costing skips both complications because the entire output is one uniform product, so a single cost sheet for the whole period gives the answer directly.
What are the benefits and limitations of unit costing
Unit costing provides a business with a clear, comparable cost figure that feeds directly into pricing decisions, tender quotes and budget targets, and it is simple enough for a small manufacturing unit to maintain without a dedicated costing department.
However, the method assumes every unit made is identical, so it does not work well once a business starts offering variants, sizes or grades of the same product, and it can mask cost differences that arise from machine breakdowns, seasonal output changes or a mix of raw material batches. A business growing out of a single product line usually needs to move toward batch or process costing to keep its cost figures meaningful.
Conclusion
The number that matters most in unit costing is not the cost sheet itself but how often it gets updated. A cost sheet drawn up once a year is a historical record, while one updated every month or after every production run becomes a tool a business can act on before a cost increase eats into margin.
TallyPrime's cost centre feature lets a business allocate material, labour and overhead expenses to specific departments or production units as each transaction is recorded, so the figures on a unit cost sheet need to stay current without a separate exercise at the end of the period.
