To be precise, the NATO target is 5% of GDP. The US spends 13.3% of its budget on defense, but only 3.4% of GDP.
>...In 2006, NATO Defence Ministers agreed to commit a minimum of 2% of their Gross Domestic Product (GDP) to defence spending to continue to ensure the Alliance's military readiness.
>...The combined wealth of the non-US Allies, measured in GDP, is almost equal to that of the United States. However, non-US Allies together spend less than half of what the United States spends on defence.
https://www.nato.int/cps/em/natohq/topics_67655.htm#:~:text=...