EconomicsConsumer TheoryA-Level
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Marginal Utility (MU) Calculator

The additional satisfaction gained from consuming one more unit of a good.

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Marginal Utility

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Overview

Marginal utility measures the additional satisfaction or benefit a consumer gains from consuming one extra unit of a good or service. It is a fundamental concept in consumer theory that helps explain how individuals allocate their resources to maximize total utility.

Symbols

Variables

MU = Marginal Utility, U = Change in Utility, Q = Change in Q

MU
Marginal Utility
utils
Change in Utility
utils
Change in Q
units

Apply it well

When To Use

When to use: This formula is used when evaluating how changes in consumption levels affect a consumer's overall satisfaction. It is most applicable in scenarios involving rational choice theory and the derivation of demand curves, assuming that other variables like price and income remain constant.

Why it matters: It explains the Law of Diminishing Marginal Utility, which states that as more of a good is consumed, the satisfaction from each additional unit decreases. This principle is vital for businesses when setting prices and for understanding the paradox of value between essential and luxury goods.

Avoid these traps

Common Mistakes

  • Confusing marginal utility with total utility.
  • Not using the difference between total utility values.

One free problem

Practice Problem

A consumer's total utility increases from 100 units to 135 units after consuming one additional serving of a dessert. Calculate the marginal utility of that serving.

Change in Utility35 utils
Change in Q1 units

Solve for: MU

Hint: Subtract the initial utility from the final utility to find the change in utility, then divide by the change in quantity.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. Mankiw, N. Gregory. Principles of Economics. 8th ed. Cengage Learning, 2018.
  2. Samuelson, Paul A., and William D. Nordhaus. Economics. 19th ed. McGraw-Hill Education, 2010.
  3. Wikipedia: Marginal utility
  4. Mankiw, N. Gregory. Principles of Economics. 9th ed. Cengage Learning, 2021.
  5. Nicholson, Walter, and Christopher Snyder. Microeconomic Theory: Basic Principles and Extensions. 12th ed. Cengage Learning, 2017.
  6. Krugman, Paul, and Robin Wells. Microeconomics. 5th ed. Worth Publishers, 2018.
  7. Microeconomics — Revenue Theory