Unraveling MPS: Calculating the Marginal Propensity to Save

Learn how to calculate the Marginal Propensity to Save (MPS) and its significance in economic behavior and savings patterns.


The Marginal Propensity to Save (MPS) is a concept in economics that measures how much additional income will be saved rather than spent. In other words, it represents the change in saving resulting from a change in income. To calculate the MPS, you can use the following formula:

MPS = Change in Saving / Change in Income

Here's a step-by-step guide on how to calculate the Marginal Propensity to Save:

  1. Determine the Change in Saving (ΔS): To calculate the change in saving, you need to compare the initial level of saving (S1) with the final level of saving (S2) after a change in income. The formula for change in saving is:

    ΔS = S2 - S1

  2. Determine the Change in Income (ΔY): Calculate the change in income by comparing the initial income level (Y1) with the final income level (Y2) after the change. The formula for change in income is:

    ΔY = Y2 - Y1

  3. Calculate the Marginal Propensity to Save (MPS): Once you have the values for the change in saving (ΔS) and the change in income (ΔY), you can use the MPS formula to find the marginal propensity to save:

    MPS = ΔS / ΔY

To provide a numerical example, let's say a household's initial income (Y1) is $50,000, and they save $5,000 of this income. After a change in circumstances or income, their income (Y2) increases to $60,000, and their saving (S2) increases to $6,000.

  1. Calculate the Change in Saving (ΔS):ΔS = S2 - S1ΔS = $6,000 - $5,000ΔS = $1,000

  2. Calculate the Change in Income (ΔY):ΔY = Y2 - Y1ΔY = $60,000 - $50,000ΔY = $10,000

  3. Calculate the Marginal Propensity to Save (MPS):MPS = ΔS / ΔYMPS = $1,000 / $10,000MPS = 0.1 or 10%

In this example, the Marginal Propensity to Save (MPS) is 0.1 or 10%. This means that for every additional dollar of income, this household saves 10 cents, while the remaining 90 cents are spent. MPS is an important concept in economics as it helps in understanding how changes in income affect saving and consumption patterns.

How to Calculate Marginal Propensity to Save.

To calculate marginal propensity to save (MPS), you use the following formula:

MPS = (Change in savings) / (Change in income)

For example, if you have a change in savings of $100 and a change in income of $500, your MPS would be 0.2. This means that for every $1 increase in income, you save $0.20.

Here is an example of how to calculate MPS:

Let's say you earn $1,000 per month and you save $100 per month. Your MPS would be 0.1, because you save $0.10 for every $1 you earn.

If you get a raise and start earning $1,200 per month, and you increase your savings to $200 per month, your MPS would be 0.17, because you save $0.17 for every $1 you earn.

MPS is an important economic measure because it helps us to understand how consumers save and spend their money. It can also be used to predict how consumers will respond to changes in the economy, such as tax cuts or interest rate hikes.

Here are some factors that can affect MPS:

  • Income: People with higher incomes tend to save more money than people with lower incomes.
  • Wealth: People with more wealth tend to save more money than people with less wealth.
  • Age: Younger people tend to save less money than older people.
  • Family size: People with larger families tend to save less money than people with smaller families.
  • Economic conditions: People tend to save more money during economic downturns and less money during economic booms.

MPS is an important economic measure that can be used to understand how consumers save and spend their money. It can also be used to predict how consumers will respond to changes in the economy.