Laos uses the Lao Kip (LAK) as its currency.
The bank notes (see pictures below) currently in circulations are 500, 1,000, 2,000, 5,000, 10,000, 20,000, 50,000, and 100,000 Kip. No coins are currently in use in Laos.
Many websites refer to the unit of Laos money as "New Kip". This maybe because the Lao Kip has been through some changes in recent times, see history of Lao Kip below.
In 1945 the Lao currency was called Free Kip.
In 1952 it was called Royal Kip, the kip was also called piastre in French. In that era, there were both coins and banknotes.
In 1976 Pathet Lao Kip replaced Royal Kip following the Pathet Lao's takeover of the country.
In 1979 Lao PDR Kip or Lao Kip or New Kip replaced Pathet Lao Kip (100 Pathet Lao Kip = 1 Kip (Lao New Kip)).
The 1979 Lao Kip, initially came in 1, 5, 10, 20, 50 and 100 Kip denominations. The 500 Kip notes were added in 1988 followed by 1,000 Kip in 1992, 2,000 and 5,000 kip notes in 1997, 10,000 and 20,000 kip notes in 2002, 50,000 kip in 2006 and 100,000 kipnotes in 2012.
At present no notes under 500 Kip are in circulation.
Lao Coins: Coins were removed from circulation many years ago.
You can exchange Lao Kip on your arrival in major airports in Laos and main ports of entry such as Lao-Thai Friendship bridge, but the exchange rates are usually lower than those in town. You cannot buy Lao Kip outside the country.
In most provinces of Laos, currency exchange offices/units are readily available (at the banks and in most big markets). Exchange rates vary from bank to bank, but are usually not that much different.
It is important to remember that as you cannot exchange or use Lao Kip outside Laos, you need to make sure you have changed it back to a currency you can use elsewhere before you leave the country.