Money and its functions

Definitions of Money in the United Kingdom
The Bank of England uses four measures of money – M0, M2, M4, and M3H, where M0 is the narrowest, and M4 is the broadest.
1. M0 consists of currency in circulation plus bankers’ deposits at the Bank of England.
2. M2 includes all the items in M0, plus retail bank deposits.
3. M4 includes all the items in M2, certificates of deposits, and wholesale bank and building society deposits.
4. M3H is an additional measure create to allow comparisons with money definitions used by the ECB. It includes all the items in M4, plus foreign currency deposits in banks and building societies.
Definitions of Money in Australia
The Reserve Bank of Australia uses three measures of money – M1, M3, and Broad Money, where M1 is the narrowest and Broad Money the broadest.
1. M1 consists of coins and bills in circulation plus bank current deposits from private non-bank entities.
2. M3 consists of all the items in M1 plus other deposits from building societies and credit unions with banks.
3. Broad Money includes the items in M3, plus borrowings from the private sector by non-bank depository corporations excluding holdings of currency and deposits of non-bank depository corporations.
Definitions of Money in Japan
The Bank of Japan uses three measures of money – M1, M2, and M3, where M1 is the narrowest and M3 the broadest.
1. M1 includes coins and bills in circulation plus deposits.
2. M2 includes the items in M1, plus certificates of deposit.
3. M3 includes the items in M2, plus savings and deposits at financial institutions and post offices.
Summary

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  The definitions of money vary by country but generally always include at least a measure for narrow money and one for broad money.
  
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  The measures are generally indicated by an M followed by one or more digits/letters.
  
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  The different measures used by central banks significantly affect the comparability of money across markets.
  
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  Only a few central banks, such as the Bank of England, issue additional measures of money to help comparisons with other economies.