Economies of scale

Topic: Production Function, Returns and Costs · NCERT: Beyond NCERT

Meaning

Economies of scale are the cost savings a firm gets when it produces on a larger scale. As output grows, long-run average cost (LRAC), the cost per unit when the firm can change all its inputs, goes down.

• Formula: LRAC = TC / q, where TC is total cost and q is the quantity of output.
• There are economies of scale while LRAC falls as q rises.

This matters because firms that stay small keep high costs and cannot compete. India's many small, low-productivity firms are a direct example, and it is why the government runs policies like PLI to help firms grow.

Explanation

How it works: the cost side of returns to scale

• Long run: a period long enough for the firm to change all its inputs, including plant size. So there is no fixed cost, and TC = TVC (total cost equals total variable cost).
• Returns to scale: what happens to output when all inputs rise in the same proportion.
• Economies of scale are the cost-side reason for increasing returns to scale (IRS). Scale means volume, i.e. producing more of the same thing.
• Numerical check (input prices fixed):
• Inputs are doubled, so cost doubles. Output rises 2.5 times.
• New average cost = 2 / 2.5 = 0.8 of the old level.

• LRAC falls 20%. This is economies of scale.

• Worked example (all costs in ₹):

q	TC	LRAC = TC/q	LRMC = TC(q) − TC(q−1)
1	12	12.00	12
2	20	10.00	8
3	26	8.67	6
4	32	8.00	6
5	40	8.00	8
6	54	9.00	14

• From q = 1 to 4, LRMC (long-run marginal cost, the extra cost of one more unit) is below LRAC, so LRAC falls from ₹12 to ₹8. This is the economies-of-scale stretch.
• LRAC first reaches its lowest level (₹8) at q = 4. This is the minimum efficient scale (MES), the smallest output at which LRAC is at its minimum.
• At q = 6, LRMC (₹14) is above LRAC, so LRAC rises to ₹9. This is diseconomies of scale.

Internal economies of scale (from the firm's own growth)

• They move the firm down along its own LRAC curve.

Type	Source	Example
Technical	Large machines that cannot be split into smaller parts; dimensional economies	A tank twice as tall and wide holds about 8 times as much but uses only about 4 times the steel
Managerial	Specialist managers for finance, HR and marketing	One expert's salary is spread over lakhs of units
Marketing and purchasing	Discounts for buying in bulk; advertising cost spread over more units	A ₹10 crore ad campaign costs ₹10 per unit on 1 crore units, but ₹100 per unit on 10 lakh units
Financial	Credit is cheaper and easier to get	Big firms borrow at lower interest and can raise money through bonds and shares
Risk-bearing	Many products and markets	A loss in one market is balanced by gains in another

External economies of scale (from the industry's growth)

• They come from the growth of the whole industry or cluster, not of one firm.
• They shift the whole LRAC curve of every firm downward.
• Sources:
• input suppliers and repair shops close by;
• a pool of skilled workers already trained in the trade;
• shared infrastructure such as roads, power, testing labs and ports;

• knowledge spillovers, where ideas spread from firm to firm.

• Alfred Marshall called such places "industrial districts".

Limits: diseconomies of scale and the shape of LRAC

• Beyond a certain size, LRAC rises. These are diseconomies of scale, the cost side of decreasing returns to scale (DRS).
• Internal causes: too many layers of management and slow decisions; top managers who cannot watch everything; scarce inputs that become costlier.

• External causes: congestion (traffic, pressure on power and water); rising land rents and wages in crowded clusters.

• So LRAC is U-shaped: it falls (IRS), then stays flat (CRS, constant returns to scale), then rises (DRS).

• Many real industries have an L-shaped or saucer-shaped LRAC. Costs fall fast at first and then stay flat over a long stretch. So firms of quite different sizes can have almost the same costs.
• MES decides how many firms a market can support. Number of efficient firms ≈ market demand ÷ MES.
• Example: the market buys 1,00,000 units and MES is 25,000 units, so about 4 firms can survive at lowest cost.
• If MES is close to the whole market, one firm can supply everything most cheaply. This is a natural monopoly (power grids, railway tracks, water pipelines).

In India

• Clusters (external economies): Tiruppur (knitwear), Surat (diamonds and textiles), Ludhiana (hosiery and bicycles), Moradabad (brassware), Sivakasi (fireworks and printing) and Bengaluru (IT). Small firms here share workers, suppliers and infrastructure, so they get some of the cost advantages that big firms have.
• Firm "dwarfism": many Indian MSMEs (micro, small and medium enterprises) stay small for decades and never reach MES. So their costs stay high and productivity stays low. This is from the Economic Survey 2018-19, Vol. 1, Chapter 3, "Nourishing Dwarfs to become Giants" [1].
• Why firms stay small:
  • size-based incentives, meaning benefits given only to firms below a size limit, plus rigid labour laws with size limits [1];
  • growing means losing the benefits, so the firm stays small;
  • it never reaches MES, so its LRAC stays high.

• Survey's fix: every size-based incentive should have a sunset clause of less than ten years, meaning it ends automatically. Existing beneficiaries keep their benefits until then, which is called grandfathering [1].

• Production Linked Incentive (PLI) schemes: the government pays firms cash linked to their extra (incremental) sales of goods made in India. This pushes them to grow to global scale [2].

• 14 sectors, including mobile phones, pharmaceuticals, automobiles, specialty steel, solar PV modules, ACC batteries and drones [2].
• Outlay: ₹1.97 lakh crore (about US$ 26 billion) at announcement [2]; ₹1.91 lakh crore in a later PIB release [3].
• As on 31 December 2025: 836 applications approved; investment over ₹2.16 lakh crore; sales over ₹20.41 lakh crore; exports over ₹8.3 lakh crore; over 14.39 lakh direct and indirect jobs; ₹28,748 crore of incentives paid [3][4].
• As on 31 March 2026: investment over ₹2.40 lakh crore and over 14.15 lakh jobs [5]. The two releases count jobs differently, so always quote a job figure with its date.
• Link to theory: PLI rewards extra output, so it rewards firms that move down their LRAC curve, i.e. firms that capture internal economies of scale.

Don't confuse with

• Returns to scale: this is about output (what happens to output when all inputs rise together). Economies of scale are about cost (what happens to LRAC). IRS is the output side; falling LRAC is the cost side.
• Economies of scope: savings from variety, when one firm makes several products that share inputs (Amul: milk, butter, cheese and ghee from one milk network). Economies of scale are savings from volume.
• Law of variable proportions: a short-run law, where only one input changes. It explains the U-shape of SAC (short-run average cost). Economies and diseconomies of scale explain the U-shape of LRAC.
• Internal vs external economies: internal economies are a movement along the firm's LRAC. External economies shift the whole LRAC down for every firm in the industry.

Prelims Hooks

• Economies of scale = LRAC falls as output rises. They are the cost side of increasing returns to scale. Diseconomies of scale are the cost side of decreasing returns to scale.
• Trap: internal economies move the firm along its LRAC. External economies (clusters, skilled labour pool, knowledge spillovers) shift LRAC down. Marshall called such clusters "industrial districts".
• MES = the lowest output at which LRAC reaches its minimum. If MES ≈ total market demand, the result is a natural monopoly.
• In the long run TC = TVC, since there is no fixed cost. LRMC cuts LRAC from below at LRAC's minimum, where CRS holds.
• "Nourishing Dwarfs to become Giants" is from Economic Survey 2018-19. It recommends a sunset clause of under 10 years on size-based incentives [1].
• PLI: 14 sectors; incentive linked to incremental sales; outlay ₹1.97 lakh crore at announcement and ₹1.91 lakh crore in a later PIB release [2][3].

Mains Points

• Scale, productivity and jobs: many Indian firms are "dwarfs" that work below MES, so they have high costs and cannot compete globally. Sunset clauses on size-based incentives [1] and support for firms to grow (PLI [2][3]) help them reach MES and create formal jobs. Use this in GS-III answers on manufacturing, MSMEs and employment.
• Clusters as a policy tool: external economies let small firms in Tiruppur, Surat, Ludhiana and Sivakasi get big-firm cost advantages. This supports common facility centres and industrial corridors. But congestion diseconomies (land rents, wages, traffic) mean land, housing and transport must be planned alongside.
• Scale vs competition, and the PLI debate:
• Where MES is large compared with the market (railways, power grids, pipelines), a natural monopoly forms. Such sectors need a regulator rather than free entry (GS-II).
• PLI shows leverage: investment over ₹2.40 lakh crore (31 March 2026) [5] against ₹28,748 crore paid out (31 December 2025) [3].
• Two questions are still open: how much value is added in India (simple assembly versus deep manufacturing), and whether the scale will last once the incentives end.

Related concepts

• Long run average cost
• Long run marginal cost
• Internal economies of scale
• External economies of scale
• Diseconomies of scale
• Economies of scope
• Minimum efficient scale

Read more

• Long-run costs: LRAC, LRMC and economies of scale and scope