Private Savings Calculator (Y − T + TR − C, public & national saving)

Understanding the private saving calculator — concept and principle

This calculator splits a country's saving into private saving by households and public saving by the government, using the national income accounting identities taught in introductory macroeconomics. It also shows national saving and whether the government runs a surplus or deficit.

Households save 230 of 880; the government spends 50 more than it collects, leaving national saving of 180.

How it is calculated

Disposable income = Y + TR − T (income plus transfers minus taxes).
Private saving = Y + TR − T − C.
Public saving = T − G − TR (negative when the government runs a deficit).
National saving = private + public = Y − C − G (transfers cancel out).
Private saving rate = private saving ÷ disposable income.

The principle

Households can either spend their disposable income or save it; what they do not spend is private saving. The government collects taxes and spends on purchases and transfers; any surplus is public saving. When the two are added, transfers drop out, because what the government pays out households receive. In a closed economy national saving equals investment. With trade, the identity becomes S + (T − G) = I + (X − M), linking saving, investment and the current account.

Worked example

Default inputs: Y = 1,000, T = 200, TR = 80, C = 650, G = 170.

Disposable income = 1,000 + 80 − 200 = 880.
Private saving = 880 − 650 = 230; private saving rate = 230 ÷ 880 ≈ 26.1%.
Public saving = 200 − 170 − 80 = −50: a budget deficit.
National saving = 230 − 50 = 180 (check: 1,000 − 650 − 170 = 180).

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

National income or GDP (Y)	Private saving
250	-520
500	-270
750	-20
1,000	230
1,250	480
1,500	730
2,000	1,230

How to read the result

A government deficit reduces national saving unless households save more. In a closed economy, lower national saving means less investment; in an open economy it can be offset by borrowing from abroad, which shows up as a current account deficit. Higher private saving can finance both investment and government deficits.

Common mistakes

Counting transfers as government purchases (G); transfers are not purchases of goods and services.
Using GDP instead of disposable income for the saving rate.
Forgetting that public saving can be negative.
Confusing saving (a flow) with wealth (a stock).

Keep in mind: This is a simplified textbook framework. Official statistics include depreciation, net foreign income and other items. For learning, not policy analysis.

Frequently asked questions

What is private saving?

The part of household disposable income not spent on consumption.

What is the difference between private and national saving?

National saving adds public saving (the government surplus or deficit) to private saving.

Why do transfers cancel out?

They reduce public saving and increase household income by the same amount.

Sources: Mankiw, N. G., Macroeconomics (national income accounting, saving and investment) · United Nations et al., System of National Accounts 2008 (saving)

Checked 9 Nov 2026. S. Nag & NSCC (adapt.), “Introduction to Macroeconomics” (2023, CC BY-SA), section 7.2 “Savings and Investment” (S_private = Y + TR − C − T, S_public = T − G − TR, national saving = Y − C − G); OpenStax, “Principles of Economics”, 3rd ed., section 23.4 “The National Saving and Investment Identity”.

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