Types of Profit - AP Microeconomics

SECTION 1

Historical Context & Motivation

The question of what constitutes "profit" has occupied economic thinkers for centuries, yet the answer depends critically on who is asking and why. An accountant tallying a firm's books and an economist analyzing market behavior will arrive at different figures for the same firm — not because one is wrong, but because they define costs differently. This conceptual split between accounting profit and economic profit lies at the heart of modern microeconomic theory and is central to understanding how firms make entry, exit, and production decisions.

1776 • Adam Smith's Wealth of Nations

Smith distinguished between the "natural price" of a commodity and the returns needed to compensate land, labor, and capital, planting early seeds of opportunity cost reasoning.

1871 • Marginalist Revolution

Jevons, Menger, and Walras formalized the idea that the cost of any choice includes the value of the next-best alternative forgone, establishing the concept of opportunity cost.

1890 • Marshall's Principles of Economics

Alfred Marshall codified the distinction between explicit and implicit costs and introduced normal profit as the minimum return needed to keep a firm in an industry.

1930s • Perfect Competition Theory Matures

Economists such as Joan Robinson and Edward Chamberlin refined the zero-economic-profit long-run equilibrium condition that remains a cornerstone of AP Microeconomics.

The central question this lesson addresses is deceptively simple: when a firm reports "positive profit" on its income statement, is it truly earning more than the full cost of all resources deployed — including the owner's time and the capital tied up in the business? Understanding the answer requires mastering the distinction between explicit costs, implicit costs, and the three profit categories that flow from them.

SECTION 2

Core Principles & Definitions

Before distinguishing types of profit, we must first separate costs into two categories. Explicit costs are direct, out-of-pocket payments a firm makes to outside suppliers of inputs — wages paid to workers, rent for a storefront, raw material purchases, and utility bills. These appear on the firm's financial statements. Implicit costs, by contrast, represent the opportunity cost of using owner-supplied resources — the income the entrepreneur forgoes by not deploying those resources in their next-best alternative use. Together, explicit and implicit costs constitute total economic cost.

Accounting Profit

Total revenue minus explicit costs only. This is the figure reported on a firm's income statement and used for tax purposes. It ignores the opportunity cost of owner-supplied resources.

Economic Profit

Total revenue minus all costs (explicit + implicit). Also called supernormal or abnormal profit, it measures whether a firm earns more than the minimum needed to keep all resources in their current use.

Normal Profit

The level of accounting profit at which economic profit equals zero. It represents the implicit cost of entrepreneurship — the minimum return that prevents the owner from exiting the industry.

Explicit vs. Implicit Costs

Explicit costs involve monetary payments to external parties. Implicit costs involve the value of self-owned resources (owner's time, foregone interest on invested capital, use of own building).

SECTION 3

Visual Explanation — Breaking Down Revenue into Cost Layers

View A shows the accountant's perspective: total revenue ($200,000) minus explicit costs ($150,000) yields an accounting profit of $50,000. View B adds implicit costs ($60,000), revealing a negative economic profit of −$10,000. The firm earns positive accounting profit but negative economic profit, meaning it is not covering the full opportunity cost of all resources.

The diagram above illustrates a firm with total revenue of $200,000. From the accountant's viewpoint (View A), the firm is profitable — it covers its explicit costs and has $50,000 remaining. But from the economist's viewpoint (View B), the owner's opportunity costs of $60,000 must also be subtracted. Because $50,000 in accounting profit falls short of the $60,000 needed to cover implicit costs, economic profit is negative $10,000. The firm would be better off if the owner redeployed resources to their next-best alternative.

SECTION 4

Mathematical Framework

ACCOUNTING PROFIT

π_accounting = TR − Explicit Costs

where TR = Total Revenue (P × Q), and explicit costs include wages, rent, materials, and other out-of-pocket expenses.

ECONOMIC PROFIT

π_economic = TR − (Explicit Costs + Implicit Costs)

Equivalently: π_economic = Accounting Profit − Implicit Costs. Economic profit accounts for the full opportunity cost of all resources, including the owner's time and capital.

NORMAL PROFIT CONDITION

π_economic = 0 ⟹ TR = Explicit Costs + Implicit Costs

When economic profit equals zero, the firm earns exactly normal profit — the minimum return needed to keep the entrepreneur in the current industry. Accounting profit is positive and equals implicit costs.

A key relationship to internalize: Accounting Profit = Economic Profit + Implicit Costs. Because implicit costs are always non-negative, accounting profit is always greater than or equal to economic profit. A firm can report positive accounting profit while simultaneously earning negative economic profit — the scenario depicted in Section 3. Conversely, if economic profit is positive, the firm is earning above what all its resources could command elsewhere, which attracts new entrants in competitive markets.

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AP EXAM TIP

SECTION 5

Three Profit Scenarios for a Competitive Firm

In perfect competition, a firm is a price taker: it faces a horizontal demand curve at the market price. Whether the firm earns positive, zero, or negative economic profit depends on the relationship between price and average total cost (ATC) at the profit-maximizing output where MR = MC. The following diagram shows all three scenarios side by side.

Panel A: Price exceeds ATC at the profit-maximizing quantity → the green shaded rectangle represents positive economic profit. Panel B: Price equals the minimum of ATC → zero economic profit (normal profit). Panel C: Price is below ATC → the red shaded rectangle represents economic loss.

In Panel A, the market price is high enough that the firm's per-unit revenue exceeds its per-unit total cost at the MR = MC output level, generating positive economic profit equal to (P − ATC) × Q. This attracts new firms, shifting the market supply curve rightward and driving the price down until economic profit reaches zero. Panel B shows the resulting long-run equilibrium where P = minimum ATC and economic profit is zero — the firm earns normal profit only. Panel C illustrates a price below ATC, resulting in economic losses; firms exit, supply decreases, and price rises back toward the zero-economic-profit equilibrium.

SECTION 6

Worked Example

Suppose Maria runs a small bakery. She left her job as a pastry chef at a hotel, where she earned $55,000 per year, and invested $100,000 of her savings (which had been earning 5% annual interest) into the bakery. Last year the bakery's financial records showed: total revenue = $250,000; wages paid to employees = $90,000; rent = $30,000; ingredient costs = $50,000; utilities and other expenses = $15,000.

Worked example

1
Step 1 — Total Explicit Costs

Sum all out-of-pocket payments: $90,000 (wages) + $30,000 (rent) + $50,000 (ingredients) + $15,000 (utilities) = $185,000.

Explicit Costs = $185,000
2
Step 2 — Accounting Profit

Subtract explicit costs from total revenue: $250,000 − $185,000 = $65,000.

Accounting Profit = $65,000
3
Step 3 — Total Implicit Costs

Foregone salary: $55,000. Foregone interest on invested savings: 5% × $100,000 = $5,000. Total implicit costs = $55,000 + $5,000 = $60,000.

Implicit Costs = $60,000
4
Step 4 — Economic Profit

Subtract both explicit and implicit costs from total revenue: $250,000 − ($185,000 + $60,000) = $250,000 − $245,000 = $5,000. Alternatively: Accounting Profit − Implicit Costs = $65,000 − $60,000 = $5,000.

Economic Profit = $5,000
5
Step 5 — Interpretation

Maria earns $5,000 more than her resources could earn in their next-best use. The bakery generates a positive economic profit, so she has no incentive to exit. Normal profit for Maria is $60,000 — the accounting profit level at which economic profit would equal zero.

Normal Profit = $60,000 (the level of accounting profit where π_economic = 0)

SECTION 7

Comparing the Three Types of Profit

Feature	Accounting Profit	Economic Profit	Normal Profit
Formula	TR − Explicit Costs	TR − (Explicit + Implicit Costs)	Implicit Costs (i.e., accounting profit when π_econ = 0)
Includes Implicit Costs?	No	Yes	Is the implicit cost
Used By	Accountants, IRS, financial reports	Economists analyzing market efficiency	Economists defining long-run equilibrium
Firm Decision Signal	Tax liability and financial health	Entry/exit decisions in a market	Break-even threshold for staying in industry
Long-Run Competitive Equilibrium	Positive (equals implicit costs)	Zero	Being earned exactly

Comparison of the three profit types

SECTION 8

Connection to Market Structure & Long-Run Equilibrium

Concept	Perfect Competition	Imperfect Competition (Monopoly, Oligopoly, Mon. Comp.)
Short-Run Economic Profit	Possible (positive, zero, or negative)	Possible (often positive due to market power)
Long-Run Economic Profit	Zero — free entry/exit eliminates it	Can persist if barriers to entry exist (monopoly, oligopoly); zero for monopolistic competition
Entry/Exit Mechanism	Free entry and exit shift supply until P = min ATC	Barriers impede entry; supernormal profits may persist indefinitely
Role of Normal Profit	Defines the long-run resting point for all firms	Still the opportunity cost benchmark, but firms may exceed it

How profit types interact with market structure

The types of profit you have learned connect directly to the broader AP Microeconomics curriculum. In later units you will see that monopolists and oligopolists can sustain positive economic profit in the long run because barriers to entry prevent the competitive entry process that drives economic profit to zero. For monopolistic competition, free entry still drives economic profit to zero in the long run, but the firm does not produce at minimum ATC due to product differentiation. Understanding the zero-economic-profit condition in perfect competition provides the baseline against which all other market structures are evaluated.

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

A perfectly competitive firm is earning zero economic profit in the long run. Which of the following statements is true?

A. The firm's total revenue equals zero.
B. The firm's accounting profit is zero.
C. The firm is covering all explicit and implicit costs, including the opportunity cost of the owner's resources.
D. The firm should exit the industry because it is not making any profit.

Show answer (C)

C is correct. Zero economic profit means total revenue exactly covers both explicit and implicit costs — the firm earns normal profit, which is the minimum needed to keep the entrepreneur in the industry. A is wrong because total revenue covers all costs, so it is a large positive number. B is wrong because accounting profit equals implicit costs when economic profit is zero, so accounting profit is positive. D is wrong because zero economic profit means the firm has no incentive to exit — it is earning exactly what its resources could earn elsewhere.

Question 2: BASIC CALCULATION

A firm has total revenue of $300,000, explicit costs of $200,000, and implicit costs of $70,000. What is the firm's economic profit?

A. $100,000
B. $30,000
C. $70,000
D. $230,000

Show answer (B)

B is correct. Economic profit = TR − (Explicit Costs + Implicit Costs) = $300,000 − ($200,000 + $70,000) = $300,000 − $270,000 = $30,000. A ($100,000) is the accounting profit, which subtracts only explicit costs. C ($70,000) is the implicit cost itself, not a profit figure. D ($230,000) incorrectly subtracts only the implicit costs from total revenue.

Question 3: INTERMEDIATE

A competitive firm produces 500 units at a market price of $12. Its average total cost at 500 units is $10, and its implicit costs total $1,500. What is the firm's accounting profit?

A. $1,000
B. $2,500
C. $3,500
D. $5,000

Show answer (C)

C is correct. First, note that economic profit = (P − ATC) × Q = ($12 − $10) × 500 = $1,000. Since economic profit = accounting profit − implicit costs, we have accounting profit = economic profit + implicit costs = $1,000 + $1,500 = $3,500. A ($1,000) is the economic profit, not accounting profit. B ($2,500) results from an arithmetic error. D ($5,000) incorrectly uses total revenue minus ATC without multiplying by quantity properly.

Question 4: APPLIED

Dr. Patel leaves her $120,000-per-year hospital position to open a private practice. She invests $200,000 of personal savings that had been earning 4% annually. In her first year, the practice earns $400,000 in total revenue and incurs $250,000 in explicit costs. (a) Calculate Dr. Patel's accounting profit. (b) Calculate her economic profit. (c) Should Dr. Patel remain in private practice? Explain using economic reasoning.

Show answer

(a) Accounting profit = TR − Explicit Costs = $400,000 − $250,000 = $150,000. (1 point) (b) Implicit costs include foregone salary ($120,000) and foregone interest (4% × $200,000 = $8,000), totaling $128,000. (1 point) Economic profit = Accounting Profit − Implicit Costs = $150,000 − $128,000 = $22,000. (1 point) (c) Yes, Dr. Patel should stay in private practice. Her economic profit is positive at $22,000, meaning her total revenue exceeds the full opportunity cost of all resources deployed. She is earning $22,000 more than she could in her next-best alternative. (1 point)

Question 5: CRITICAL THINKING

Consider a perfectly competitive industry that is currently in long-run equilibrium. (a) Draw a correctly labeled side-by-side graph showing the market (supply and demand) and a representative firm (MC, ATC, and demand/MR). Identify the equilibrium price (P*), quantity for the market (

Q_M

), and quantity for the firm (q*). (b) Explain why economic profit is zero at this equilibrium and identify the firm's accounting profit in terms of its cost structure. (c) Suppose consumer demand increases. On your graph, show the short-run effect on the market and the firm. Identify the type of profit the firm now earns. (d) Explain the long-run adjustment process that returns the industry to zero economic profit. Reference entry/exit and the effect on market supply.

Show answer

(a) The market graph shows an upward-sloping supply curve and a downward-sloping demand curve intersecting at equilibrium price P* and market quantity

Q_M

. (1 point) The firm graph shows U-shaped MC and ATC curves, with a horizontal demand/MR line at P*. P* must be tangent to the minimum point of ATC. (1 point) The firm produces q* where MR = MC. (1 point) (b) At long-run equilibrium, P* = minimum ATC. Since economic profit = (P − ATC) × q, and P = ATC, economic profit equals zero. The firm earns zero economic profit but positive accounting profit equal to its implicit costs — this is normal profit, the minimum return needed to keep the entrepreneur in the industry. (1 point) (c) An increase in consumer demand shifts the market demand curve rightward from D₁ to D₂. In the short run, the market price rises to P₂ > P*. (1 point) On the firm graph, the horizontal demand/MR line shifts up to P₂, which now lies above the ATC curve at the new MR = MC output. The rectangular area between P₂ and ATC (times quantity) is positive economic profit. (1 point) (d) Positive economic profit signals to entrepreneurs outside the industry that returns exceed opportunity costs, causing new firms to enter. (1 point) Entry shifts the market supply curve rightward from S₁ to S₂, increasing total quantity supplied and driving the market price back down. Entry continues until P falls back to the minimum of ATC and economic profit returns to zero. At this point, no further incentive for entry or exit exists, and the industry is in a new long-run equilibrium at a lower price (equal to the original P* if costs are constant) but a higher market quantity. (1 point)