What to look for when you receive cash

When someone hands you cash, you can spot a counterfeit or damaged bill by checking a few physical features that are hard to fake. Real U.S. currency has a security thread embedded in the paper, a watermark that matches the portrait, color-shifting ink in the bottom right corner, and a raised texture you can feel. Counterfeit bills often feel too smooth, have blurry printing, or lack the security thread entirely.

Start by running your thumb across the bill. Genuine currency has a slightly rough texture from the cotton-linen blend used in printing. The portrait should be sharp and detailed, not fuzzy or flat-looking. Hold the bill up to light — you should see a watermark on the right side that matches the face on the front, and a security thread running vertically through the paper with text printed on it.

Check the color-shifting ink in the lower right corner of the front side. Tilt the bill and watch the number change color from copper to green. This effect is nearly impossible to reproduce on a counterfeit. Also look for tiny red and blue fibers embedded in the paper itself — not printed on top, but woven into the bill.

Key Takeaways

  • Real U.S. bills have a security thread you can see when held to light, a watermark matching the portrait, and color-shifting ink in the corner.
  • Genuine currency has a slightly rough texture from cotton-linen paper, while counterfeits often feel too smooth or waxy.
  • Red and blue fibers are embedded in the paper itself, not printed on the surface, and the portrait printing should be sharp and detailed.
  • If you receive a bill you suspect is counterfeit, do not spend it — contact your bank or the U.S. Secret Service.

How to check bills by denomination

Newer bills (printed after 2013) have additional security features that older bills lack. The $100 bill has a blue security ribbon woven into the paper with bells and 100s that appear and disappear as you tilt it. The $50, $20, $10, and $5 bills all have color-shifting numbers in the lower right corner and security threads specific to each denomination.

Older bills still in circulation have fewer security features, which is why they are easier to counterfeit. If you receive a bill from before 2000, check it more carefully. The security thread should still be present, and the watermark should still match the portrait when held to light. Bills printed between 2000 and 2013 have some security features but not all of the newest ones.

The $1 bill has the fewest security features of any denomination, which makes it a common target for counterfeiters. Look for the security thread, the watermark, and the fine-line pattern in the background. The portrait of George Washington should be sharp and three-dimensional in appearance.

What to do if you receive a counterfeit or damaged bill

If you believe a bill is counterfeit, do not try to spend it or return it to the person who gave it to you. Take it to your bank and explain where you received it. Banks have procedures for handling suspected counterfeits and can send them to the Federal Reserve for examination. You will not be penalized for turning in a counterfeit bill you received unknowingly.

If a bill is damaged — torn, stained, or partially destroyed — you can exchange it at your bank or mail it to the Bureau of Engraving and Printing. For bills that are more than half intact, your bank can usually exchange them on the spot. For bills that are less than half intact or severely damaged, you will need to fill out a form and mail the bill to the Bureau, which can take several weeks.

Keep the damaged bill in a safe place while you wait for an exchange. Do not attempt to tape it back together or clean it, as this can make it harder to verify. If you are mailing it to the Bureau, include a letter explaining what happened to the bill and your contact information.

Understanding security features on modern bills

The U.S. Treasury has added security features to currency over the past 20 years to stay ahead of counterfeiters. The most recent redesigns focus on features that are visible to the naked eye but difficult to replicate with standard printing equipment. These include the security thread, watermark, color-shifting ink, and fine-line patterns in the background.

The security thread is a thin strip of plastic or paper embedded in the bill during printing. Each denomination has a thread with different text and position. The $100 thread says "USA 100," the $50 says "USA 50," and so on. When you hold the bill to light, the thread appears as a solid line running vertically through the paper.

The watermark is created by varying the thickness of the paper during printing. It appears as a faint image on the right side of the bill that matches the portrait on the front. The watermark is visible from both sides of the bill when held to light, and it should be in the same position as the portrait.

Why counterfeiting happens and how it affects you

Counterfeiting is a federal crime, but it still occurs because some people believe they can profit by creating fake bills. Most counterfeits are produced using high-quality printers and scanners, but they still lack the fine details and security features of genuine currency. The U.S. Secret Service investigates counterfeiting cases and works with law enforcement to catch and prosecute counterfeiters.

If you unknowingly receive and spend a counterfeit bill, you are not liable for the loss — the loss falls on the business or person who received it from you. However, if you knowingly pass a counterfeit bill, you can be charged with a federal crime. This is why it is important to check bills when you receive them and report suspected counterfeits to your bank.

Counterfeiting affects the economy by reducing the value of genuine currency and increasing inflation. It also increases costs for businesses, which must invest in bill-checking equipment and training. By checking your cash and reporting counterfeits, you help protect the integrity of U.S. currency.

Tools and methods for checking cash at home

You do not need special equipment to check most bills — your eyes, hands, and a light source are usually enough. A simple desk lamp or flashlight is sufficient to see the watermark and security thread. If you handle large amounts of cash regularly, you might consider a counterfeit detection pen, which uses iodine to test the paper. Genuine currency paper does not react to the pen, while counterfeit paper usually does.

Ultraviolet (UV) light can also reveal security features that are invisible under normal light. Many newer bills have features that glow under UV light, such as hidden images or text. You can purchase a small UV flashlight online for under $20 if you want to check bills this way, but it is not necessary for everyday use.

The most reliable method is still the basic check: feel the texture, look at the portrait, hold it to light to see the watermark and security thread, and check the color-shifting ink. If all of these features are present and correct, the bill is almost certainly genuine.

Common mistakes people make when checking cash

One common mistake is assuming that a bill is real just because it feels thick or has color. Counterfeiters have become skilled at mimicking the weight and appearance of genuine bills, so these alone are not reliable indicators. Another mistake is checking only one feature — a counterfeit might have a security thread but lack the watermark, or vice versa. Always check multiple features before deciding a bill is genuine.

People also sometimes confuse damaged bills with counterfeits. A bill that is torn, faded, or stained is not necessarily counterfeit — it may simply be old or worn. Damaged bills can still be exchanged at your bank, so there is no need to worry if you have one. The key difference is that a counterfeit will lack the core security features, while a damaged genuine bill will still have them.

Finally, some people trust their initial impression too much. If you are unsure about a bill, take time to check it carefully rather than assuming it is fine. If you still have doubts after checking, take it to your bank and let them verify it. Banks have access to more detailed information and equipment than most people do at home.

Frequently Asked Questions

Can I use a counterfeit detection pen on all bills?

Counterfeit detection pens work on most bills, but they are not 100 percent reliable. The pen tests the starch content in the paper — genuine currency has low starch, while counterfeit paper often has higher starch. However, some counterfeits use paper with low starch, so a negative result does not may provide the bill is real. Use the pen as one tool among several, not as the only check.

What should I do if a business gives me a counterfeit bill as change?

Take the bill back to the business and explain that you received it as change. Most businesses will exchange it for genuine currency without question. If they refuse, you can report the incident to your local police department or the U.S. Secret Service. Keep your receipt if you have one, as it can help document when and where you received the bill.

Are old bills harder to verify than new ones?

Older bills have fewer security features, which can make them slightly harder to verify, but the basic features like the security thread and watermark are still present. Bills printed before 1990 have the fewest security features, so check them more carefully. If you are unsure about an old bill, your bank can verify it for you.

How long does it take to exchange a damaged bill at the bank?

If more than half of the bill is intact, most banks can exchange it immediately. If less than half is intact, you will need to mail it to the Bureau of Engraving and Printing, which typically takes two to four weeks. Include a letter explaining what happened and your contact information with the damaged bill.

Is it illegal to have a counterfeit bill if I didn't know it was fake?

No, it is not illegal to have a counterfeit bill if you received it unknowingly and did not try to spend it. Once you realize it is counterfeit, you should report it to your bank or the U.S. Secret Service. It only becomes illegal if you knowingly pass a counterfeit bill to someone else.