Check the security strip for “USA 100” when held to light
Look for the blue 3D security ribbon woven into the bill
Hold the bill to light to see the watermark of Benjamin Franklin
Tilt the bill to see the color-shifting 100 in the lower right corner
Feel the raised printing on the portrait, numbers, and text
Verify the microprinting around the portrait and security features
Check that the paper feels crisp and not like regular printer paper
Compare the bill to a known genuine $100 bill
Use a counterfeit detection pen only as a rough check
Look for clear, sharp details and consistent color
Check that the serial numbers match and are evenly spaced
Make sure the Federal Reserve and Treasury seals are crisp and well-defined