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Class 11 Micro Economics Notes · CBSE

Short Run and Long Run

Short Run and Long Run — understanding the two time periods in production analysis and how factor flexibility differs. CBSE Class 11 Microeconomics notes with comparison table.

Last updated: 25 Aug 2026

Notes

Short Run and Long Run

Class 11 Microeconomics — Understanding the time periods in production analysis

Short Run

Short Run
Short run refers to a period in which output can be changed by changing only variable factors. In the short run, fixed inputs like plant, machinery, building, etc. cannot be changed. It means, production can be raised by increasing variable factors, but till the extent of capacity of fixed factors.

Real-World Example

If a producer wants to increase output in the short run, this can be achieved by using more raw materials and increasing the number of workers with the existing factory building, plant, and equipment. One cannot immediately expand the factory building or install additional plant and equipment.

Think of a chai stall:The stall has one cart (fixed). To make more chai in the evening rush, you buy more tea leaves and milk (variable) — but you can't suddenly build a second cart in 2 hours. That's the short run.

Long Run

Long Run
Long run refers to a period in which output can be changed by changing all factors of production. Long run is a period that is long enough for the firm to adjust all its inputs according to change in the conditions. In the long run, the firm can change its factory size, switch to new techniques of production, purchase new machinery, etc.

Real-World Example

After years of operating one chai stall, the owner decides to open a second stall across town, hire more staff, buy better equipment, and even start supplying chai to office canteens. Allinputs are being changed — that's the long run.

Key Clarification

The distinction between short run and long run does not refer to a calendar period and is not based on a fixed time span. The period is rather a functional concept, which depends on production conditions. It varies from firm to firm and industry to industry.

Steel Industry

10 years may be the short run — building a new steel plant takes that long.

Wheat Producer

1 year may be the long run — switching crops and buying new equipment is possible within a season.

Comparison: Short Run vs Long Run

Short Run vs Long Run
AspectShort RunLong Run
MeaningPeriod in which output can be changed by changing only variable factorsPeriod in which output can be changed by changing all factors of production
ClassificationFactors are classified as variable and fixedAll factors are variable
Price DeterminationDemand is more active — supply cannot be increased immediately with increase in demandBoth demand and supply play equal role — both can be increased

Key Takeaways

Key Takeaways

  • Short run = only variable factors can be changed; fixed factors remain the same.
  • Long run = ALL factors of production become variable.
  • The distinction is functional, not calendar-based — it varies by firm and industry.
  • In the short run, a firm can only expand output within the capacity of its fixed factors.
  • In the long run, the firm can change its entire scale of operations.