Take it to a bank, they will be able to tell you if it really is genuine.
Now a days there are security features on the 100 dollar bills to help you detect if the bill is counterfeit or not. One of the features is a watermark. If you hold the bill up to the light you will see a faint image of Benjamin Franklin to the right of the portrait.
cut it
The US did print 10,000 dollar bills. Since these are of a higher denomination and more scarce than 1,2,5,10 and 20 dollar bills there is a higher chance that it is a counterfeit bill. However just because there is a higher chance does not mean that it is fake. The best way to find out if it is fake is to take it to trusted and experienced collector. He or she will probably be able to tell you.
The serial number and most times the letter on the bill.
2 Twenties Dollar bills 1 Five Dollar bill 1 One Dollar bill
Verifying if a 1950 one hundred dollar is counterfeit can be done in a number of ways. Initially check for a thread pattern in the paper. US currency has paper with a rag content including visible threads. then check for a watermark. A watermark cannot be xeroxed properly. Finally, the disclosure pen found at retail stores can check the chemical content of the paper to verify authenticity.
Trade dollars were only made from 1873 to 1875 and have the words TRADE DOLLAR in large letters on the back. Anything else is a fantasy piece or a counterfeit.
The year should be printed on the front of the bill
Not many fake coins are made from real silver or gold. Take it to a jeweler to be tested, most will do this for you.
shine a one dollar bill at the sun. then take the 2 dollar bill and put it on a black or brown flat surface and shine a uv pens light on the bill if you see the back of the bill its real if you don't its fake
well see... there are numbers on a bill and in your case it is... $20
The fact that you are holding it indicates it is fake. There is no such thing as a million dollar bill and one has never been printed.