You’re standing at a busy register, or maybe you're selling a used couch on Facebook Marketplace. Someone hands you a crisp Benjamin. It feels okay, right? But something in the back of your mind twitches. That tiny doubt is usually your best friend because, honestly, the Secret Service seized about $21.8 million in counterfeit currency in 2023 alone. Most of that was passed into the hands of regular people who didn't know how to spot a counterfeit 100 bill until the bank teller gave them the bad news.
Fake money is a weirdly personal crime. When you accept a bad bill, you’re the one out of luck. The bank won't reimburse you. The police just take it as evidence. You basically just gave your product or service away for free.
The Texture Trap: Why the Paper is Everything
Most people think the "pen" is the ultimate test. It isn't. Those iodine pens just react to starch in wood-based paper. If a counterfeiter uses "bleached" singles—literally washing the ink off a $1 bill and printing a $100 over it—the pen will say it's real. It's a classic trick.
Real U.S. currency isn't actually paper. It’s a 75% cotton and 25% linen blend produced exclusively by Crane & Co. It has a specific "snap" when you flick it. If it feels greasy, overly smooth, or like a standard sheet of printer paper, you've likely got a fake.
Run your fingernail across Benjamin Franklin’s shoulder. On a genuine 100, you’ll feel distinct ridges. This is intaglio printing, a process where the ink is literally piled onto the paper. It’s incredibly hard to replicate with standard inkjet or laser printers which usually produce flat, dull images. If the portrait feels smooth as a whistle, start asking questions.
Checking the 3D Security Ribbon
Look at the blue ribbon woven into the center of the bill. It’s not printed on the paper; it’s threaded through it. If you see a fake where the blue line looks like it’s just sitting on top, or if you can peel it off with a fingernail, it’s a wrap.
But here’s the cool part: the 3D ribbon has bells and "100s" inside it. When you tilt the bill back and forth, the bells change to 100s. If you move the bill side to side, the images move up and down. If you move the bill up and down, the images move side to side. It’s counterintuitive. Counterfeiters usually can't get that "opposite movement" right. Most fakes just have a static holographic strip that glitters but doesn't actually dance.
The Bell in the Inkwell
There is a copper-colored inkwell located to the right of Franklin. Inside that inkwell is a bell. This is one of the most sophisticated features of the Series 2004 and later notes.
- Color-shifting magic: When you tilt the bill, the bell should change from copper to green.
- The disappearing act: This effect makes the bell appear and disappear within the inkwell.
- The 100 in the corner: The large "100" in the bottom right corner also shifts from copper to green.
If that ink stays one solid color no matter how you move it, you’re looking at a fake. Genuine color-shifting ink is incredibly expensive and highly regulated. Most scammers use metallic glitter paint or cheap iridescent powders that don't have that clean, crisp transition between colors.
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Transparency and the Watermark
Hold the bill up to a light source. You should see a faint image of Benjamin Franklin in the blank space to the right of the portrait. It should match the main portrait exactly.
Here is where it gets tricky. On some high-quality counterfeits, they actually print a faint image on the back to mimic a watermark. However, a real watermark is inside the paper and is visible from both sides. It’s subtle. If the watermark looks like a dark, heavy-handed drawing, or if the "watermark" Ben looks like he’s had some bad plastic surgery (distorted eyes or nose), it’s a counterfeit.
While you're holding it up to the light, look for the security thread to the left of the portrait. It’s a thin vertical strip that says "USA" and "100" in an alternating pattern. In the sun, it’s visible. Under a UV light, that specific thread should glow pink. Not blue, not green—bright pink.
Microprinting and the "Blur" Factor
Grab a magnifying glass if you have one, or just use the zoom on your phone camera. Real money is insanely detailed. On the $100 bill, look for "THE UNITED STATES OF AMERICA" on Franklin’s coat collar and "USA 100" in the space where the watermark sits.
Counterfeiters struggle with the edges. Their text often looks blurry or "bloody" under magnification because the ink bleeds into the paper fibers. On a real bill, the lines are sharp enough to perform surgery with. Even the fine lines in the background of the portrait should be distinct, not a muddy grey smudge.
What to Do When You Find a Fake
Don't be a hero. If you’re in a transaction and realize the bill is bad, try to delay the person if it’s safe, but don't put yourself in danger.
- Observe: Get a good look at the person and their vehicle.
- Handle with care: Put the bill in an envelope. Try not to touch it too much; the Secret Service can actually pull prints or DNA off these bills in some cases.
- Call the authorities: Contact your local police or the nearest U.S. Secret Service field office.
- Write your initials: Put your initials and the date on the border of the bill so you can identify it later if needed.
People often think they can just "pass it on" to someone else to get their money back. Don't do that. Knowingly passing counterfeit currency is a federal felony that carries up to 20 years in prison. It’s not worth it for a hundred bucks.
Actionable Tips for Daily Use
Stay sharp. You don't need a lab to protect your pocketbook.
- Trust your hands first. If the paper feels like a flyer you got on your windshield, it's probably junk.
- Tilt it every time. The color-shifting ink in the bottom right corner is the hardest thing for low-level scammers to fake.
- Look for the pink glow. If you run a business, buy a cheap UV flashlight. They cost ten bucks and save you hundreds.
- Compare it. If you have another $100 in your wallet that you know is real, lay them side-by-side. The differences in the "fine line" work on the border will usually jump right out at you.
- Check the serial numbers. On many fakes, scammers use the same serial number for an entire batch. If someone hands you three bills and they all have the same number, you've just found a printer's mistake.