And on top of that the state income taxes in most states, and sales taxes that usually approach 8 or 9%, and property taxes on real estate (and autos where I live). Also if you manage to save anything after all that, you can look forward to paying dividend or capital gains taxes (a form of double taxation).
Most other countries have twice that sales tax, as well as having all those other taxes. The best rough estimate of taxation burden might be proportion of government spending of GDP, which IIRC is about 35% for US, and is lower than eg most European countries.
You need to take into account what you get in addition to what you pay.
In American those taxes provide a strong military. Most of the rest of the world are very poorly equipped by comparison. Other countries get health care and education.
Improving foreign policy would be a cheap way to reduce military costs - relying on a militia was the American tradition up until the Cold War and is indeed one of the reasons you have the right to arms.
It is a myth that America is a low tax nation.