Thevelocity of money measures the number of times that one unit of currency is used to purchase goods and services within a given time period.^[3] In other words, it's how many times money is changing hands. The concept relates the size of economic activity to a givenmoney supply, and the speed of money exchange is one of the variables that determineinflation. The measure of the velocity of money is usually the ratio of thegross national product (GNP) to a country's money supply.

If the velocity of money is increasing, then transactions are occurring between individuals more frequently.^[3] The velocity of money changes over time and is influenced by a variety of factors.^[4]

Because of the nature of financial transactions, the velocity of money cannot be determined empirically.

If, for example, in a very small economy, afarmer and amechanic, with just $50 between them, buy new goods and services from each other in just three transactions over the course of a year

• A farmer spends $50 ontractor repair from a mechanic.
• The mechanic buys $40 ofcorn from the farmer.
• The mechanic spends $10 onbarn cats from the farmer.

then $100 changed hands in the course of a year, even though there is only $50 in this little economy. That $100 level is possible because each dollar was spent on new goods and services an average of twice a year, which is to say that the velocity was${\displaystyle 2/\text{year}}$. If the farmer bought a used tractor from the mechanic or made a gift to the mechanic, it would not go into the numerator of velocity because that transaction would not be part of this tiny economy'sgross domestic product (GDP).

The velocity of money provides another perspective onmoney demand. Given the nominal flow of transactions using money, if theinterest rate on alternative financial assets is high, people will not want to hold much money relative to the quantity of their transactions—they try to exchange it fast for goods or other financial assets, and money is said to "burn a hole in their pocket" and velocity is high. This situation is precisely one of money demand being low. Conversely, with a lowopportunity cost, velocity is low and money demand is high. Both situations contribute to the time-varying nature of the money demand.^[5] In money marketequilibrium, some economic variables (interest rates, income, or the price level) have adjusted to equate money demand and money supply.^{[citation needed]}

The quantitative relation between velocity and money demand is given by Velocity =Nominal Transactions (however defined) divided by Nominal Money Demand.

In practice, attempts to measure the velocity of money are usually indirect. The transactions velocity can be computed as

${\displaystyle V_T=\frac{PT}{M}}$

where

${\displaystyle V_T}$ is the velocity of money for all transactions in a given time frame;

${\displaystyle P}$ is theprice level;

${\displaystyle T}$ is the amount oftransactions occurring in a given time frame; and

${\displaystyle M}$ is the total nominal amount ofmoney in circulation on average in the economy (see “Money supply” for details).

Thus${\displaystyle PT}$ is the total nominal amount of transactions per period.

Values of${\displaystyle PT}$ and${\displaystyle M}$ permit calculation of${\displaystyle V_T}$.

Similarly, the income velocity of money may be written as

${\displaystyle V=\frac{PQ}{M}}$

where

${\displaystyle V}$ is the velocity for transactions counting towardsnational or domestic product;

${\displaystyle Q}$ is an index ofreal expenditures (on newly produced goods and services); and

${\displaystyle PQ}$ is nominalnational or domestic product.

The determinants and consequent stability of the velocity of money are a subject of controversy across and withinschools of economic thought. Those favoring aquantity theory of money have tended to believe that, in the absence ofinflationary ordeflationary expectations, velocity will be technologically determined and stable, and that such expectations will not generally arise without a signal that overall prices have changed or will change.

This determinant has come under scrutiny in 2020-2021 as the levels of M1 and M2 Money Supply grow at an increasingly volatile rate while Velocity of M1 and M2^[3] flattens to stable new low of a 1.10 ratio. While interest rates have remained stable under the Fed Rate, the economy is saving more M1 and M2 rather than consuming, in the expectations that Fed benchmark interest rate increases from all-time lows of 0.50%. During this time, inflation has risen to new decade highs without the velocity of money.

Ludwig von Mises in a 1968 letter toHenry Hazlitt said: "The main deficiency of the velocity of circulation concept is that it does not start from the actions of individuals but looks at the problem from the angle of the whole economic system. This concept in itself is a vicious mode of approaching the problem of prices and purchasing power. It is assumed that, other things being equal, prices must change in proportion to the changes occurring in the total supply of money available. This is not true."^[6]

• Cramer, J.S. “velocity of circulation”,The New Palgrave: A Dictionary of Economics (1987), v. 4, pp. 601–02.
• Friedman, Milton; “quantity theory of money”, inThe New Palgrave: A Dictionary of Economics (1987), v. 4, pp. 3–20.

• Velocity of money data – from the St. Louis Fed's FRED database

• Monetary economics
• Freiwirtschaft
• Demand for money
• Macroeconomic indicators

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