Flowing hair and Gobrecht silver dollars are both 40mm diameter. Edited by coretj 02/16/ am. Report this Post to the Staff Go to Top of. There are approximately billion one dollar bills in circulation in the US, with billion 20 dollar bills and billion dollar bills. There are about Coins of the United States dollar were first minted in New coins have been produced These "steel pennies" are not likely to be found in circulation today, as they were later intentionally removed from circulation for See also US coin sizes, showing all major U.S. coin series and scaled images in a single chart.