The rupiah (Rp) is the official currency of Indonesia. Issued and controlled by the Bank of Indonesia, the ISO 4217 currency code for the Indonesian rupiah is IDR. The symbol used on all banknotes and coins are Rp. The name derives from the Indian monetary unit rupee. Informally, Indonesians also use the word "perak" ('silver' in Indonesian) in referring to rupiah. The rupiah is subdivided into 100 sen, although inflation has rendered all coins and banknotes denominated in sen obsolete.

The Riau islands and the Indonesian half of New Guinea (Irian Barat) had their own variants of the rupiah, but these were subsumed into the national rupiah in 1964 and 1971 respectively (see Riau rupiah and West New Guinea rupiah).

Indonesian rupiah coinage was first issued in 1951 and 1952, a year or so later than the first Indonesian rupiah banknotes printed following the peace treaty with The Netherlands, agreed in November 1949. Although revolutionary currency had been issued in by the provisional Republic of Indonesia between the declaration of independent on 17 August 1945 and 1949, it had all been formed of paper, metal being far too scarce for the internationally isolated government to use as currency.

Due to high inflation in the late 1950s and early 1960s, no coins were minted after 1961, and that which remainied in circulation was effectively worthless.

A devalued 'new rupiah' was issued in an attempt to tame inflation in 1965, with banknotes in denominations all the way from 1 sen (1 cent) up to 100 rupiah - no coins were struck at this time. By 1971, however, the economy, and inflation, under Suharto's New Order was stable, and coinage was once again issued, in denominations of 1, 5, 10, 25 and 50 rupiah, with 100 rupiah added two years later. Due to inflation, the current coinage now consists of 25, 50, 100, 200, 500 and 1000 rupiah, although older 1 rupiah coins remain officially legal tender for completeness.

The first paper money used in the Indonesian archipelago was that of the United East Indies Company, credit letters of the rijksdaalder dating between 1783 and 1811. Netherlands Indian gulden government credit paper followed in 1815, and from 1827 gulden notes of De Javasche Bank. Lower denominations (below 5 gulden) were issued by the government in 1919-1920 and 1939-1940, due to wartime metal shortages, but otherwise day-to-day transactions were conducted using coinage.

Gulden notes were issued by 'The Japanese Government' during the occupation from 1942, becoming 'roepiah' in 1943.

The first truly Indonesian rupiah notes, however were issued in 1946, during the war of independence with the Dutch, following the unilateral declaration of independence by the Indonesians at the end of World War Two on 17 August 1945. This money is known as 'Oeang Republik Indonesia' ('oeang' being the old spelling of 'uang', in English 'money').

Following the negotiated peace treaty in The Hague of 1949, the 'ORI' was withdrawn, to be replaced by an internationally recognised 'Indonesian rupiah'.

There are two current issues of Indonesian banknotes the 2000-2001 notes of 1000 and 5000 rupiah, and the the 2004, 2005 notes of higher denominations (10000, 20000, 50000 and 100000 rupiah), with better anti-forgery devices. The 1998-1999 notes are no longer legal tender since 31 January 2008 (but will be exchangeable for 10 years at Bank Indonesia). Earlier notes are also no longer legal tender, due to the lack of security features and association with the Suharto regime, but can be exchanged in Bank Indonesia offices until 2010.

By 1992, the rupiah was worth less than one fifth of what it had been worth when the 10,000 rupiah note had been introduced in 1970, and so a 20,000 rupiah note was produced, then the largest note ever seen in Indonesia.

The Asian financial crisis of 1997-1998 reduced the rupiah's value by over 80% in a few months and was a major factor in the overthrow of President Suharto's government. The rupiah had traded at about 2000-3000 rupiah per 1 USD, but reached a low of 16,800 rupiah per dollar in June 1998. The currency, which had been relatively stable in prior years, had its value destroyed. The government did not take any action to demonetise or revalue the banknotes, "Direksi 1998" merely redesigned the 10,000 and 20,000 rupiah notes.

"Direksi 1999" saw a new Soepratman design for the 50,000 rupiah, replacing the commemorative note of Suharto, who had been deposed after more than 30 years as Indonesia's dictator in the wake of the crisis.

"Direksi 2000" brought a new 1,000 rupiah note, with the 100 and 500 rupiah notes having been discontinued due to the dramatic devaluation of Indonesia's currency.

"Direksi 2001" redesigned the 5,000 rupiah, while "Direksi 2004" brought an end to the polymer 100,000 rupiah notes, replacing with a paper design, as well the issue of a new more secure 20,000 rupiah note.

The most recent changes to Indonesian money were "Direksi 2005", which re-designed the 10,000 and 50,000 rupiah note.

The rupiah declined from its relatively strengthened position at the end of the financial crisis, with the rupiah seeing in the century at 7,050 to the US$, but declining to 9,725 by the end of 2000, and reaching a low of 12,069 on 27th April 2001. The currency strengthened to 8,500 later in 2001, but ended 2001 at 10,505. March 2002 saw the currency break below 10,000, from which point the currency maintained a rate in the 8000s and 9000s until August 2005, and in the latter half of that year, the trading range extended towards 11,000, but ending the year just below 10,000. 2006 and 2007 saw the currency trade in a relatively narrow range against the US$ (which itself was depreciating against other currencies), of 8500-9900. This trend continued into 2008, with the currency trading between 9000 and 9500.

The Financial crisis of 2007–2008 with the collapse in the commodities market saw the US$ gain strongly against currencies backed by weakening commodities exports. With palm oil and rubber prices falling from their peak by more than half, the rupiah came under pressure, Bank Indonesia spent $7 billion of its $57 billion reserves in October defending the currency.[11] Despite this, the rupiah began to fall. and the rupiah slipped below 10,000 on 23rd October for the first time since 2005, and then below 11,000 on 2nd November, a mark last reached in 2001. On November 13th, Bank Indonesia introduced new regulations requiring foreign currency purchases over $100,000 a month to be backed by documentation of an underlying transaction and a tax number. The rupiah closed below 12,000 for the first time since 1998 on 20th October, with intraday lows below 13,000 hit. Subsequently, however, the cut in the Federal Reserve rate to 0-0.25% and Bank Indonesia support for the currency, saw the rupiah strengthen slightly to a range around 11,000.

The leu ([lew], plural: lei [lej]; ISO 4217 code RON; numeric code 946) is the currency of Romania. It is subdivided into 100 bani (singular: ban). On 1 July 2005, Romania underwent a currency reform, switching from the previous leu (ROL) to a new leu (RON). 1 RON is equal to 10,000 ROL.

Romania joined the European Union on 1 January 2007 and it is expected to adopt the euro in 2014.

On August 15, 1947, a revaluation took place, with a new leu replacing the old one at a rate of 20,000 old lei = 1 new leu. This revaluation, called a monetary reform or stabilisation measure (mica stabilizare, marea stabilizare), was carried out by the Communist authorities with absolutely no advance warning and without the possibility to exchange more than a fixed amount of money for the new currency. This was done in order to depose the former middle and upper classes of their last assets, after nationalization, to prepare for collectivization and to finalize the installation of communism. At the time of its introduction, 150 new lei equalled 1 U.S. dollar.

In the 1990s, after the downfall of communism, inflation ran high due to reform failures, the legalization of owning foreign currency in 1990, and the bankrupt policies of the former communist era, reaching rates as high as 300% per year in 1993. By September 2003, one euro was exchanged for more than 40,000 lei, this being its peak value. Following a number of successful monetary policies in the late 1990s and early 2000s, the situation became gradually more stable, with one digit inflation in 2005.

The Romanian leu briefly held the dubious distinction of being the world's least valued currency unit, from January (when the Turkish lira dropped six zeros) to July 2005. However, the 1,000,000 lei bill was not the highest Romanian denomination ever. This distinction belongs to the 5 million lei bill from 1947.

On 1 July 2005, the leu was revalued at the rate of 10,000 "old" lei (ROL) for one "new" leu (RON), thus psychologically bringing the purchasing power of the leu back in line with those of other major Western currencies. The term chosen for the action was "denominare", similar to the English "denomination", to signify not a conversion, but rather a total reinvention.

The first day brought difficulties adjusting to the new paper currencies and closed ATMs (that needed reprogramming) and forcing a new calculation habit that slowed down shops and annoyed some salespeople and shoppers. The old ROL currency banknotes remained in circulation until December 31, 2006 (coins remained in circulation only until December 31, 2005), but all accounts have been converted starting July 1, 2005. There is no conversion time limit between the currencies. Retailers had to display prices in both old and new currency from March 1, 2005 until June 30, 2006. The appreciation of the leu during 2005 was about 20% against a basket of major currencies.

As of 2006, the revaluation is a potential source of confusion, especially to visitors, since both old and new currency values are commonly quoted. When written, the very large amounts in old currency are usually obvious, but in speaking inhabitants might refer to an amount of 5 new lei as simply "fifty" in reference to its value 50,000 old lei.

In 1952, coins were introduced in denominations of 1, 3, 5, 10 and 25 bani, with the 1, 3 and 5 struck in aluminium bronze and the others in cupro-nickel. In 1955, cupro-nickel 50 bani were added.

In 1960, a new coinage was introduced, consisting of 15 and 25 bani, with 5 bani, 1 and 3 lei coins added in 1963. All were struck in nickel-clad steel. In 1975, aluminium replaced steel in the 5 and 15 bani, with the same change happening for the 25 bani in 1982. Aluminium 5 lei were introduced in 1978.

Following the end of the communist regime, a new coinage was introduced between 1990 and 1992, consisting of 1 leu in bronze clad steel, 5 and 10 lei in nickel plated steel, 20 and 50 lei in brass clad steel and nickel plated steel 100 lei.

As inflation took its toll, 500, 1000 and 5000 lei coins were introduced in 1999, 2000 and 2001, respectively, and were the only coins circulating when the revaluation occurred. They were all criticized for being clumsy and difficult to use. The 500 lei coins were very thick (about 0.3 cm). Despite their small value, it took only a handful of such coins to fill one's pocket. They were also made of poor material and could be occasionally found with bite marks. The 1000 lei coin was considered too small and was also cheaply made, and the 5000 lei coin was not circular (it was a dodecagon). This made it awkward to handle and difficult to use in slot machines, where it was frequently the only coin accepted. The 500, 1000 and 5000 lei coins became worth 5, 10 and 50 bani with the revaluation.

In 1952, the Ministry of Finance introduced notes for 1, 3 and 5 lei, and the Banca Republicii Populare Romane introduced 10, 25 and 100 lei notes. In 1966, the Banca Nationala a Republicii Socialiste Romania took over the production of all paper money, issuing notes for 1, 3, 5, 10, 25, 50 and 100 lei.

In 1991, 500 and 1000 lei notes were introduced, followed by 200 and 5000 lei notes in 1992, 10,000 lei in 1994, 50,000 lei in 1996, 100,000 lei in 1998, 500,000 lei in 2000 and 1 million lei in 2003. There was also a 2000 lei note, introduced in 1999; it celebrated the total solar eclipse that occurred on August 11th, 1999. The final issues of the 2000, 10,000, 50,000, 100,000, 500,000 and 1 million lei were polymer notes.

Notes in circulation at the revaluation were:

* 10,000 lei (became 1 leu)
* 50,000 lei (became 5 lei)
* 100,000 lei (became 10 lei)
* 500,000 lei (became 50 lei)
* 1,000,000 lei (became 100 lei)

In 2005, polymer notes were introduced for 1, 5, 10, 50, 100 and 500 lei. 200 lei notes were added in 2006. The designs of the 1, 5, 10, 50 and 100 lei notes are based on those of the earlier 10,000, 50,000, 100,000, 500,000 and 1 million lei notes which they replaced. The 10 lei bill was redesigned in November 2008 (most of the graphic elements are identical, some of the safety elements were withdrawn, making its safety degree similar the the lower values of 1 leu and 5 lei bills).