APC Calculator (average propensity to consume & save)

Understanding the average propensity to consume calculator — concept and principle

This calculator finds the average propensity to consume (APC), the share of disposable income that is spent, and its partner, the average propensity to save (APS). It also shows saving, spending per 100 of income and whether you are saving or dissaving. Use it for macroeconomics homework, household budgeting and understanding consumption data.

Spending $52,000 of $60,000 gives APC 0.867; the rest, 0.133, is the average propensity to save.

How it is calculated

APC = consumption ÷ disposable income (C ÷ Yd).
APS = saving ÷ disposable income = 1 − APC.
Saving = disposable income − consumption.
Spent out of every 100 = APC × 100.

APC above 1 means spending exceeds income (dissaving).

The principle

Disposable income can only be spent or saved, so the two shares must add up to 1: APC + APS = 1. In Keynesian macroeconomics, the consumption function links spending to income, and APC describes the average relationship at a given income level. It differs from the marginal propensity to consume (MPC), which measures how spending changes when income changes. Typically, APC falls as income rises, because higher-income households save a larger share.

Worked example

Default inputs: consumption $52,000, disposable income $60,000 a year.

APC = 52,000 ÷ 60,000 ≈ 0.867.
APS = 1 − 0.867 ≈ 0.133.
Saving = 60,000 − 52,000 = $8,000.
Out of every 100 of income, about 86.7 is spent.
Situation: saving part of income.

Each point is the calculator re-run with only “Disposable income (per year)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Disposable income (per year)	Average propensity to consume (APC)
15,000	3.467
30,000	1.733
45,000	1.156
60,000	0.867
75,000	0.693
90,000	0.578
120,000	0.433

How to read the result

An APC of 0.867 means about 87% of disposable income is spent and 13% saved. An APC near 1 leaves almost no saving, and above 1 means drawing on savings or borrowing. For a country, the household saving rate published by statistics agencies is closely related to APS.

Common mistakes

Using gross income instead of disposable (after-tax) income.
Confusing APC with MPC.
Including saving-like items, such as pension contributions or debt principal, as consumption.
Comparing APC across very different periods without adjusting for one-off purchases.

Keep in mind: This is a simple ratio. National statistics define consumption and disposable income in specific ways, so figures may not match published saving rates exactly. This is not financial advice.

Frequently asked questions

What is the difference between APC and MPC?

APC is total consumption ÷ total income; MPC is the change in consumption ÷ the change in income.

Can APC be greater than 1?

Yes, when spending exceeds income, financed by savings or borrowing.

Why do APC and APS add up to 1?

Disposable income is either consumed or saved, so the two shares cover the whole.

Sources: BYU–Idaho, ECON 151 web text, Lesson 6 "Basic Macroeconomic Relationships" (2013)

Checked 9 Nov 2026. Brigham Young University–Idaho, ECON 151 web text, Lesson 6 “Basic Macroeconomic Relationships” (2013): APC = C ÷ Yd, APS = S ÷ Yd, APC + APS = 1.

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