Conclusion. Dollars or dollar as a common noun is always written with a lowercase letter, with the exception of starting a sentence (such as this one) or in a title/heading. The US Dollar can be referred to as a proper noun (and capitalized) in some official documents.

Do you capitalize a currency?

Currency names should not be capitalized in normal circumstances, not even the euro. The "euro" in particular confuses a lot of people, because every other word that begins with e-u-r-o requires a capital. "Euroland", however, is a proper noun - it's an ad-hoc place name - and so ought to have a capital letter.

What is the correct way to write US dollars?

In an English document, when you need to specify the type of dollar (Canadian, American, Australian, etc.), the Translation Bureau recommends using the symbol US$ to represent the American dollar. Write the country symbol ( US ) first, immediately followed by the dollar sign ($) and the dollar figure: US$ 25.99.