Consumer Theory
Utility, diminishing returns, budget constraints, and indifference curves.
13 articles
FeaturedThe Substitution and Income Effects: A Framework for Decomposing Any Price Change
When a price changes, two distinct forces hit your wallet at once. Splitting them apart explains why you buy less — and even why a few goods defy the rule…
Read more →Deep Dives
4 articles
What Utility Means in Economics — and Why It's Not About Happiness
Utility is economics' name for how much a choice satisfies you — a ranking, not a feeling. Here is what it actually measures, and what it deliberately ignores.

The Myth That More Is Always Better: How Diminishing Marginal Utility Works
We assume twice the stuff means twice the satisfaction. Diminishing marginal utility says the second unit is almost always worth less than the first — and the…

The Budget Constraint: How Income Limits Turn Preferences Into Decisions
Wanting something is free; affording it is not. The budget constraint is the line where your income and prices decide which of your preferences you actually…

Inside Indifference Curves: What Consumer Preferences Look Like on a Graph
An indifference curve maps every combination of two goods that leaves you equally satisfied. Take it apart piece by piece and consumer choice becomes a picture.
Quick Answers
8 termsThe Substitution Effect and Income Effect: Two Reasons Demand Slopes Down
When price rises, consumers buy less for two distinct reasons: the substitution effect (the good is now relatively more expensive) and the income effect (real…
Read more →Budget Constraint: The Line That Defines What You Can Afford
A budget constraint shows all the combinations of goods a consumer can afford given their income and prices.
Read more →The Law of Diminishing Marginal Utility: Why the First Is Always the Best
The law of diminishing marginal utility states that as consumption of a good increases, each additional unit provides less additional satisfaction.
Read more →Utility Maximization: The Math Behind Consumer Choice
Utility maximization is the principle that rational consumers allocate their budgets to achieve the highest possible total satisfaction.
Read more →Indifference Curves: Mapping Consumer Preferences
An indifference curve shows all combinations of two goods that give a consumer equal satisfaction.
Read more →Marginal Utility: The Satisfaction From One More
Marginal utility is the additional satisfaction from consuming one more unit of a good. It is the key variable in every consumer decision at the margin.
Read more →Utility: The Economic Measure of Satisfaction
Utility is the satisfaction or benefit a consumer receives from consuming a good or service. It is the fundamental concept behind all consumer choice theory.
Read more →Consumer Surplus: The Hidden Value Markets Create
Consumer surplus is the difference between what a buyer is willing to pay and what they actually pay.
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