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Strategic Cost Management · Throughput Accounting

Throughput Accounting Ratio: Formula, Measures and Numericals

Updated 11 October 2026 · Fact-checked

Throughput accounting measures a product by throughput (sales less totally variable cost), compared with the factory's operating expenses. Divide throughput per bottleneck hour (return per factory hour) by total operating expenses per bottleneck hour (cost per factory hour). This is the throughput accounting ratio (TA ratio). A ratio above 1 means the product earns more than it costs to run the factory.

Understand Throughput Measures and Ratios

Throughput accounting looks at a business as a system that turns money into more money through a few scarce resources. It does not try to spread every cost over every unit. It asks one question: how fast does the factory generate cash from sales?

It uses three measures. Throughput is sales revenue less totally variable costs, which are usually direct materials and any other cost that changes with each unit sold. Labour is normally treated as a fixed cost here unless it is paid per unit. Operating expenses are all other costs of running the factory, including labour and overheads. Investments are money tied up in inventory, equipment and similar assets.

Every factory has a bottleneck, the resource that limits output. Hours on the bottleneck are scarce, so you judge each product by what it earns per bottleneck hour. This is the return per factory hour = throughput per unit ÷ bottleneck hours per unit. The cost per factory hour = total operating expenses ÷ total bottleneck hours available.

The throughput accounting ratio = return per factory hour ÷ cost per factory hour. If it is above 1, the product earns more per bottleneck hour than the factory costs per bottleneck hour, so it adds to profit. If it is below 1, it does not cover the factory's running cost. Rank products by the ratio and use scarce bottleneck time on the highest first.

Key rules to remember

Throughput
Throughput = Sales revenue − Totally variable costs (usually direct material)
Labour is a fixed operating expense unless the question says it is paid per unit.
Throughput per unit
Throughput per unit = Selling price per unit − Material cost per unit
Use this as the numerator base for return per factory hour.
Return per factory hour
Return per factory hour = Throughput per unit ÷ Bottleneck hours per unit
Also called throughput contribution per bottleneck hour.
Cost per factory hour
Cost per factory hour = Total operating expenses ÷ Total bottleneck hours available
Operating expenses are labour plus other factory costs, excluding material.
Throughput accounting ratio
TA ratio = Return per factory hour ÷ Cost per factory hour
Above 1: product adds to profit. Below 1: it does not cover factory cost. Equal to 1: break-even.
Net profit
Net profit = Throughput − Operating expenses
Useful as a cross-check on any product mix.

How to solve Throughput Measures and Ratios questions

Use this order for any throughput accounting ratio question. It keeps the units consistent and avoids mixing absolute and per-hour figures.

  1. 1Identify the bottleneck resource and the hours it has available in the period.
  2. 2Find the totally variable cost per unit, normally material, and compute throughput per unit = price − material.
  3. 3Add up all operating expenses (labour, overheads, other factory costs) for the period.
  4. 4Compute cost per factory hour = total operating expenses ÷ total bottleneck hours available.
  5. 5Compute return per factory hour for each product = throughput per unit ÷ bottleneck hours per unit.
  6. 6Compute the TA ratio for each product = return per hour ÷ cost per hour.
  7. 7Interpret: ratio above 1 adds to profit; rank products by ratio or by return per hour for allocating bottleneck time.
  8. 8If asked, build the production plan in rank order, then compute total throughput less operating expenses for profit.

Quickest way: Rank by return per factory hour

When to use it: When the question asks which product to make first, or gives several products and one limiting resource.

  1. Write price, material and bottleneck hours for each product in one row.
  2. Compute throughput per unit, then divide by bottleneck hours.
  3. Compute cost per factory hour once and reuse it for every product.
  4. Divide each return by that single cost figure to get the ratio.
  5. Rank in descending order. The ranking by return per hour equals the ranking by ratio, so you can skip the ratio if only ranking is asked.

Common mistakes in Throughput Measures and Ratios

  • Deducting labour when computing throughput

    Students carry over the idea of contribution, where labour is variable.

    Fix: In throughput accounting only totally variable cost, usually material, is deducted. Put labour in operating expenses unless told it varies per unit.

  • Using total hours of all machines for cost per factory hour

    The question lists hours for several departments.

    Fix: Use only the bottleneck hours available. Identify the bottleneck first, then divide operating expenses by those hours.

  • Inverting the ratio

    Students forget which figure is the numerator.

    Fix: Return per factory hour goes on top, cost per factory hour below. Return is what the product earns; cost is what the hour costs.

  • Ranking by throughput per unit instead of per bottleneck hour

    The highest-throughput product looks best.

    Fix: Always divide by bottleneck hours per unit before ranking. A high-throughput product that uses many hours can rank lower.

  • Misreading a ratio above 1 as a reason to make unlimited quantity

    Students treat the ratio as a go signal without checking capacity or demand.

    Fix: A ratio above 1 shows the product is worthwhile. Output is still limited by bottleneck hours and by maximum demand, so allocate in rank order.

Worked examples

Example 1

Aarav Components Ltd makes product P. Selling price ₹500 per unit, material ₹200 per unit, bottleneck time 2 hours per unit. Total factory operating expenses are ₹6,00,000 for the month and the bottleneck has 2,000 hours available. Compute return per factory hour, cost per factory hour and the TA ratio, and comment.

Show the solution
  1. Throughput per unit = 500 − 200 = ₹300.
  2. Return per factory hour = 300 ÷ 2 = ₹150.
  3. Cost per factory hour = 6,00,000 ÷ 2,000 = ₹300.
  4. TA ratio = 150 ÷ 300 = 0.5.

Answer: Return per factory hour ₹150; cost per factory hour ₹300; TA ratio 0.5. Because the ratio is below 1, P earns less per bottleneck hour than the factory costs to run. At current prices and costs it reduces profit, so review price, material cost or bottleneck usage.

Example 2

Kaveri Industries makes X and Y using one bottleneck machine with 3,000 hours available. Operating expenses are ₹9,00,000. X: price ₹400, material ₹160, 1.5 hours per unit. Y: price ₹300, material ₹120, 0.75 hours per unit. Compute the TA ratios and rank the products.

Show the solution
  1. Cost per factory hour = 9,00,000 ÷ 3,000 = ₹300.
  2. X throughput per unit = 400 − 160 = ₹240. Return per hour = 240 ÷ 1.5 = ₹160.
  3. X TA ratio = 160 ÷ 300 = 0.533 (approximately).
  4. Y throughput per unit = 300 − 120 = ₹180. Return per hour = 180 ÷ 0.75 = ₹240.
  5. Y TA ratio = 240 ÷ 300 = 0.8.
  6. Ranking by TA ratio: Y first (0.8), then X (0.533).

Answer: Y has a TA ratio of 0.8 and X about 0.533. Y ranks first and should get bottleneck time first. Both are below 1 at this cost level, so the firm must reduce operating expenses or raise throughput per hour to make either product cover the factory's cost.

Exam tips

  • Read the question for the bottleneck first. Everything else depends on it.
  • Show cost per factory hour as a separate line. Examiners award a mark for it even if later steps go wrong.
  • Write one line of interpretation after the ratio: above 1 adds to profit, below 1 does not cover cost.
  • When labour is given as a per-unit rate, check whether the question says it is fixed. Follow the question's statement about treatment.
  • In MCQs, check the ratio's direction: return ÷ cost. Wrong-way answers are common distractors.

Practice questions from Throughput Accounting

Throughput Measures and Ratios in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Throughput Measures and Ratios: frequently asked questions

What is the throughput accounting ratio formula?

TA ratio = return per factory hour ÷ cost per factory hour. Return per factory hour is throughput per unit divided by bottleneck hours per unit. Cost per factory hour is total operating expenses divided by bottleneck hours available.

What does a throughput accounting ratio greater than 1 mean?

It means the product earns more per bottleneck hour than the factory costs per bottleneck hour. Making and selling it adds to profit. Products with a higher ratio should get bottleneck time first.

How do I calculate throughput contribution per bottleneck hour?

Subtract the totally variable cost, usually material, from the selling price to get throughput per unit. Divide that by the bottleneck hours one unit needs. The result is the return per factory hour.

How is throughput different from contribution?

Contribution deducts all variable costs, often including direct labour. Throughput deducts only totally variable costs, typically material, and treats labour as an operating expense. This usually makes throughput higher than contribution.