美國政府收支不平衡從1950年到2000年，絕大多數的年份都是支出多於收入。赤字的平均約佔 GDP 的2%。2008年經濟大不景氣，赤字增加，高達 GDP 的10%，到2016年回到2.5%左右。每年的赤字把國債增加。美國國債與 GDP 比例也繼續增加。 2000年、2005年、2010年、2015年國債分別是 GDP 的55.8%， 61.4%，91.6%與101.9%。國債的增加是當前一個令人注意的經濟問題。
近年來用於社會福利的支出約佔政府總支出的一半。社會福利的支出主要包括社會保障（失業工人的補貼和年老公民的生活費用）和政府供應的醫療保險。聯邦政府總支出約等於 GDP 的20%。其中社會福利的支出約等於聯邦政府總支出的24% ，醫療保險的支出約等於聯邦政府總支出的23%。這便是說二者之和將達政府支出的一半。
During tough economic times like the Great Recession, government spending automatically increases because there is an upsurge in the number of people eligible for need-based programs like food stamps and unemployment benefits. At the same time, tax revenues tend to decrease because fewer people are employed and therefore pay less in taxes. Corporations also earn less profit, and they too pay less in taxes. What’s more, lawmakers may intentionally increase government spending during a recession in order to stimulate the economy, even though they know that the result will be a deficit.
On April 29, 2016, debt held by the public was $13.8 trillion or about 76% of the previous 12 months of GDP. Intragovernmental holdings stood at $5.3 trillion, giving a combined total gross national debt of $19.1 trillion or about 106% of the previous 12 months of GDP $6.2 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest of which were the People’s Republic of China and Japan at about $1.25 trillion for China and $1.15 trillion for Japan as of February 2016.
CBO short-term outlook
CBO reported in its February 2014 Budget and Economic Outlook (which covers the 2014-2024 period) that deficits were projected to return to approximately the historical average relative to the size of the economy (GDP) by 2014. CBO estimated that under current law, the deficit would total $514 billion in fiscal year 2014 or 3.0% GDP. Deficits would then slowly begin rising again through 2024 due primarily to the pressures of an aging population and rising healthcare costs per person. The debt to GDP ratio would remain stable for much of the decade then begin rising again toward the end of the 10-year forecast window, from 74% in 2014 to 79% in 2024.
National debt for selected years
On June 25, 2014, the BEA announced: “On July 30, 2014, in addition to the regular revision of estimates for the most recent 3 years and for the first quarter of 2014, GDP and select components will be revised back to the first quarter of 1999.