How can you check if a US 1 dollar bill is real?

Answer 1

The risk of finding a fake $1 bill is very low because most counterfeiters don't want to put the effort into copying such a small denomination. For that and some other reasons, $1 (and $2) bills don't have most of the anti-counterfeiting features found in higher-value banknotes. E.g. they don't have watermarks, security strips, or microprinting. You can look for the following, however:

• There should be tiny red and blue fibers visible in the paper
• The "teeth" on the two seals should be sharp and evenly spaced.
• Engraving lines, especially those on Washington's portrait, should be crisp and well-defined.