Calovskis, 30, spent 21 months in prison before he pleaded guilty in September and admitted to having written some of the computer code for the so-called Gozi virus, Reuters reported.
U.S. District Judge Kimba Wood in Manhattan called Calovskis' conduct serious but said "the goal of punishment has been served already."
David Bertan, Calovskis' lawyer, said the sentence, which also includes an order that he forfeit $1,000, could mean his client could be returned to Latvia within weeks.
The Gozi virus, used to steal personal bank account information of computer users while remaining virtually undetectable, was discovered by computer security experts in 2007.
The indictment of Calovskis was unsealed in January 2013, as prosecutors announced charges against Nikita Kuzmin, the virus' Russian creator, and Mihai Ionut Paunescu, a Romanian accused of running a service that enabled its distribution.
Calovskis had been a freelance programmer at the time of the offense. Bertan said Calovskis at the time was seeking money amid an economic crisis and his father developing cancer.
Calovskis was arrested in Latvia in 2012, but he was not extradited until February 2015.
His extradition had been held up for several months while he launched an unsuccessful appeal to the European Court of Human Rights, which rejected his claim that he would not be able to face a fair trial in the US.
The 30-year-old had faced up to 67 years in jail before entering into a plea-bargain agreement with the US government.
The Gozi virus is estimated to have hit more than one million computers worldwide including 40,000 in the US and 190 at NASA.