Check the paper texture; real bills feel crisp and slightly rough, not smooth like regular paper
Hold the bill to the light and look for the embedded security thread
Look for the watermark of Benjamin Franklin on the right side when held to light
Tilt the bill to see the color-shifting ink on the lower right corner of the front
Inspect the blue 3D security ribbon woven into the bill
Check that the portrait and details are sharp, not blurry or faded
Look for microprinting around the portrait and security features
Verify the serial numbers are evenly spaced and match each other
Compare the bill to a known genuine $100 bill
Use a counterfeit detection pen only as a quick check, not a final test
Check for raised printing by lightly rubbing the portrait and numbers
Examine the Federal Reserve and Treasury seals for clarity and correct placement
Use a UV light to confirm the security thread glows the correct color
Be cautious if the bill feels too thick, too thin, or unusually glossy
If unsure, have the bill checked by a bank or law enforcement