You're standing at a garage sale or maybe you're selling a used couch on Facebook Marketplace. Someone hands you a crisp Benjamin. It feels okay. It looks okay. But there is that tiny, nagging voice in the back of your head wondering if you just traded your furniture for a high-quality piece of scrap paper. Honestly, knowing how to tell if 100 bill is real isn't just for bank tellers or federal agents anymore. Counterfeiting technology has gotten scary good, and the old "marker test" is basically useless against the sophisticated fakes floating around today.
Most people think they can just feel the paper and know. That’s a mistake. The Secret Service actually points out that high-end counterfeiters often use "bleached" bills—taking a genuine five-dollar bill, scrubbing the ink off with chemicals, and printing a hundred over it. It feels like money because it was money. But it’s a fake hundred.
If you want to protect your wallet, you have to look deeper than the surface.
The blue ribbon that actually moves
When the Federal Reserve redesigned the $100 note back in 2013, they added a 3D Security Ribbon. It’s that thick blue vertical stripe down the center-right of the bill. It isn't printed on the paper. It is actually woven into the fibers.
Try this: tilt the bill back and forth while focusing on the blue ribbon. You’ll see images of bells and "100"s moving. If you tilt it vertically, they move horizontally. If you tilt it horizontally, they move vertically. It’s a trip. Most counterfeiters can’t replicate this weaving process; they usually just print a shiny blue line on top of the paper. If the bells don't dance, the bill is a dud.
The "Bell in the Inkwell" is another high-tech trick. Inside that copper-colored inkwell next to Ben Franklin, there’s a color-shifting bell. When you tilt the bill, the bell changes from copper to green. This creates an effect where the bell seems to disappear and reappear inside the inkwell. It’s subtle. You have to look for it. But if that bell stays one solid color regardless of the angle, you are looking at a counterfeit.
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Why you should stop trusting that yellow marker
We’ve all seen the cashier at the grocery store swipe a yellow highlighter across a bill. If it turns black, it’s fake. If it stays yellow, it’s "real."
Here is the problem: those pens react to starch. Standard printer paper has starch in it, while genuine currency paper (which is 75% cotton and 25% linen) does not. However, if a counterfeiter uses "mule" paper or chemically treated wood-pulp paper, they can bypass the pen entirely. Even worse, if someone uses the "bleached bill" method I mentioned earlier, the pen will show a "real" result because the paper is technically official US currency paper—it just has the wrong denomination printed on it.
Basically, the pen is a lazy man's security check. It catches the amateur who used an inkjet printer at home, but it won't catch the pros.
The texture of Benjamin Franklin’s shoulder
Run your fingernail across the shoulder of Benjamin Franklin on the left side of the bill. It should feel rough. This is due to "intaglio" printing, a process where the ink is layered so thick it creates a physical texture you can actually feel.
Most fakes feel smooth or "waxy." Genuine bills have a very specific "raised" feel that is incredibly difficult to mimic without the massive, multi-million dollar printing presses used by the Bureau of Engraving and Printing. This texture extends to the "United States of America" text and the "100" in the bottom corner.
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Hidden ghosts: Watermarks and security threads
Hold the bill up to a light. Seriously, don't be shy about it. You are looking for two specific things that should be embedded inside the paper, not printed on it.
First, look for the faint image of Benjamin Franklin in the blank space to the right of the large portrait. This is the watermark. It should be visible from both sides of the bill. A common tell on fakes is that the watermark looks "drawn" on or is too dark. On a real bill, it’s a ghostly, refined image that matches the main portrait perfectly.
Second, look for the security thread. This is a thin vertical strip to the left of the portrait. It’s thin, clear, and says "USA 100" in tiny letters. If you want to be extra sure, hit it with a UV light. That little strip will glow bright pink under ultraviolet light. If it doesn't glow, or if it glows the wrong color, get rid of it.
- 1996 - 2013 Series: These have a larger portrait but lack the blue 3D ribbon. They still have the security thread and the color-shifting ink (the "100" in the corner turns from green to black).
- Pre-1996 Series: These are the "small head" bills. They are much harder to verify because they lack almost all modern security features. They are still legal tender, but they are also the favorite target of counterfeiters because they are so simple.
Microprinting and the "blur" factor
Counterfeiters, even the good ones, usually struggle with the tiny details. Get a magnifying glass—or just use the zoom on your smartphone camera. Look at Franklin’s jacket collar. You should see the words "The United States of America" in tiny, crisp letters.
On a fake, this text often looks like a blurry line or a series of dots. This is because most counterfeiters use high-end inkjets or laser printers that rely on "dots" of color to create an image. Genuine money is printed using plates that create solid, sharp lines. If the tiny text looks "fuzzy" or "pixelated," you're holding a counterfeit.
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What to do if you actually find a fake
This is the part that sucks. If you realize you have a counterfeit bill, you can’t just go to the bank and trade it for a real one. The bank will confiscate it, and you’ll be out $100. It feels unfair, but that’s the law.
Do not try to spend it. If you knowingly try to pass a counterfeit bill, you are committing a felony. It doesn't matter if you were the victim first. Instead, the Secret Service recommends you handle the bill as little as possible to preserve fingerprints and turn it over to local police or the nearest Secret Service field office.
Actionable steps for your next cash transaction
Next time someone hands you a hundred, don't just shove it in your pocket. Do these three things immediately:
- The Thumb Scrape: Run your thumb over Ben’s shoulder. Feel for that sandpaper-like texture.
- The Blue Dance: Tilt the bill and make sure the bells on the blue ribbon move.
- The Light Check: Hold it up to any light source. Check for the Ben Franklin watermark on the right and the "USA 100" strip on the left.
If any of those three things feel "off," ask for a different bill or cancel the transaction. Most honest people won't mind you checking—it's just smart business. Counterfeiters rely on the fact that we’re usually too polite or too rushed to look closely. Taking five seconds to verify can save you a hundred dollars and a lot of legal headaches.
Check your bills. Every time. No exceptions.