How to Tell If a $100 Bill Is Real: A Complete Guide to Spotting Fake US Currency

A bill by bill, feature by feature guide, checked against the US Secret Service and the US Currency Education Program, including corrections to the popular “real vs. fake” graphics you’ve probably seen floating around.

Here’s a number worth sitting with for a second: the Federal Reserve estimates that only about 1 in every 80,000 bills in circulation is counterfeit. That works out to somewhere between fifteen and thirty million fake dollars floating around out of a currency supply worth trillions. So no, you don’t need to eye every twenty someone hands you like it’s a live grenade. Still, knowing how to spot fake dollars takes only a few seconds once you know where to look on each bill, and those seconds are worth spending.

But that small percentage still adds up to real losses for real people, and the $20 bill happens to be the single most counterfeited denomination in the country, according to the Secret Service. If you handle cash regularly, whether that’s running a shop, working a register, doing currency exchange, or just accepting cash from a stranger on Facebook Marketplace, it’s worth knowing what you’re actually looking at. It’s just as useful if you’re an Indian traveler picking up dollars before a US trip, buying from an RBI-authorised dealer means the notes have already been through this kind of check before they reach you, but it doesn’t hurt to know it yourself.

Here’s the part most guides skip over. Not every bill has the same security features. A $1 note and a $100 note are built completely differently, and a lot of “spot the fake” graphics you’ll find online blur those differences together, slapping the same checklist on every denomination whether it applies or not. I pulled six of the popular ones (the images through this guide) and checked every claim against the Secret Service’s own reference materials. A few of them get things wrong in exactly this way. I’ve flagged and corrected those as we go, so you’re not left memorising details that don’t actually exist on the bill in your hand.

Before getting into denomination-specific detail, a few US currency security features apply broadly across every bill, so let’s cover those once.

Feel the paper. Real US currency isn’t printed on regular paper stock. It’s a blend of 25% linen and 75% cotton, with tiny red and blue fibers running through it, not sitting on top of it. Genuine bills also use intaglio printing, a process that presses ink into the paper under intense pressure, so the ink sits slightly raised off the surface. Run a fingertip over the portrait or the lettering. You should feel texture. A photocopy or inkjet print is flat because, well, it is flat.

Look closely at the linework. This takes a little practice, but genuine notes have remarkably fine, crisp engraving. Fakes, even decent ones, tend to look just slightly soft around the edges. Borders that should be sharp geometric patterns come out blurry, and portraits look flat instead of carrying that engraved depth.

Match the serial numbers. Every bill has two identical serial numbers, printed in the same ink color as the Treasury seal, evenly spaced and matching in font. If one number looks even slightly off from the other, that’s worth a second look.

NO WATERMARK · NO SECURITY THREAD · NO COLOR-SHIFTING INK

Let’s start with the bill that breaks all the rules.

Here’s something a lot of people don’t realize, and it’s the biggest correction in this whole guide: the $1 bill has no watermark and no security thread. None. The design has barely changed since 1963, and the Treasury has never added the modern anti-counterfeiting tech you’ll find on $5 bills and up. There’s just no incentive to counterfeit a dollar. The juice isn’t worth the squeeze, so the government never bothered upgrading it.

So if you hold a $1 bill under a UV light expecting a thread to glow “USA 1,” you’ll be waiting a while. There’s nothing there. Same story with checking for a watermark by holding it to the light. That trick doesn’t apply here, no matter how many “cheat sheets” tell you otherwise.

What you can actually check on a $1 bill: the cotton-linen paper texture (same blend as every other denomination), the crispness of Washington’s portrait, and whether the green Treasury seal and serial numbers look evenly inked. There’s small microprinting around the border reading “THE UNITED STATES OF AMERICA,” which is genuinely hard to reproduce cleanly on consumer printing equipment.

REFERENCE: Real vs. fake $1 bill, front and back

WATERMARK + UV THREAD · NO COLOR-SHIFTING INK

The $5 is where things get genuinely interesting, and it’s also where the reference graphic below trips up.

This bill does carry real security features. Hold it to the light and you’ll see two watermarks, both small images of the numeral “5,” not Lincoln’s face the way you might expect. That’s actually unique among US bills. Every other denomination from $10 up uses a watermark that matches the portrait; the $5 uses a number instead. There’s also a genuine security thread running vertically to the right of Lincoln’s portrait, printed “USA FIVE,” glowing blue under UV light — worth flagging since it sat on the left in the pre-2008 design, and that older position is still what a lot of popular cheat sheets show.

The $5 bill does not have color-shifting ink. At all. This is confirmed directly by the Secret Service’s own currency reference material. That large purple 5 on the back is just purple, permanently. It stays exactly the same color no matter how you angle it. Color-shifting ink is a feature that starts at $10 and up. If you’re tilting a $5 bill looking for a color change, you’re testing for something that was never there, on a real bill or a fake one.

What actually works for verifying a $5: check the blue UV thread and confirm its position (right of the portrait, not left), look for the two numeral watermarks, and feel for raised printing on Lincoln’s collar and the note’s borders.

REFERENCE: Real vs. fake $5 bill, front and back

FULL SECURITY SUITE · THREAD GLOWS ORANGE, NOT BLUE

The $10 follows the standard pattern you’ll see repeated through $20, $50, and $100. It carries a watermark of Hamilton that matches his portrait, visible when held to light. Its security thread sits to the right of the portrait this time, printed “USA TEN,” and here’s a correction worth remembering: that thread glows orange under UV light, not blue. The graphic below labels it “blue security thread” as a header, a mistake that looks like it got carried over from a template used across several of these infographics. Orange is correct for a ten.

Color-shifting ink is present and accurate here. Tilt the bill and watch the “10” in the bottom right shift from a coppery tone to green. That’s been a feature since the redesigned notes entered circulation in 2000, making it one of the more reliable checks for this particular bill.

Hamilton’s portrait should show fine, engraved detail, especially in the shading of his coat and hair. Microprinting reading “USA TEN” shows up in a few spots along the border, small enough that you’d want a magnifying glass to really confirm it.

REFERENCE: Real vs. fake $10 bill, front and back

FULL SECURITY SUITE · AMERICA’S MOST FAKED NOTE · THREAD GLOWS GREEN

The $20 deserves extra attention because it’s the single most counterfeited bill in the country. More fake twenties get passed than any other denomination, and it’s not hard to see why. It’s common enough that cashiers rarely scrutinize it the way they might a hundred, but valuable enough to be worth the trouble of faking.

Jackson’s portrait has a matching watermark, visible when held to light, and the security thread sits to the left of the portrait, printed “USA TWENTY.” Here’s the correction, same issue as the ten: that thread glows green under UV light, not blue. If you’ve ever heard someone confidently claim “the twenty glows blue,” they’re actually thinking of the five.

Color-shifting ink works exactly as described in the chart below. That “20” in the bottom right should shift from copper to green when tilted. The microprinting “USA20” sits in tiny text within Jackson’s collar, and it’s one of the harder details for low-grade counterfeits to replicate cleanly.

Quick aside since it comes up a lot: Jackson is still on the $20 for now. There’s a long-running plan to eventually feature Harriet Tubman on this note, but as of mid-2026 the Treasury Department has said that redesign isn’t moving forward at present. So don’t expect the twenty in your wallet to look different anytime soon.

REFERENCE: Real vs. fake $20 bill, front and back

FULL SECURITY SUITE · STRAIGHT THREAD, NOT A RIBBON · GLOWS YELLOW

This is where the reference graphic makes its biggest mistake, so let’s clear it up properly.

The chart below labels the $50’s main security feature a “3D security ribbon,” the same kind of woven blue ribbon that visibly shifts and moves when you tilt a $100 bill. That’s not correct. The $50 does not have a 3D ribbon. It has a straight embedded security thread, the same style used on the $5, $10, and $20, positioned to the right of Grant’s portrait. The woven, moving 3D ribbon effect is genuinely unique to the $100 note and doesn’t appear on anything else in circulation. If someone describes a “$50 with a moving ribbon” to you, that’s a red flag on its own, because that’s simply not how the real bill is built.

What the $50 actually has: a straight thread printed “USA 50,” glowing yellow under UV light (not blue, and not a ribbon), a watermark of Grant matching his portrait, and color-shifting ink on the “50” numeral in the bottom right, which does correctly shift from copper to green when tilted.

Grant’s portrait should carry fine detail through his beard and uniform. The back of the note features the US Capitol, and weak or flat printing in the columns and dome is a common tell on lower-quality fakes.

REFERENCE: Real vs. fake $50 bill, front and back

FULL SECURITY SUITE · ONLY NOTE WITH A GENUINE 3D RIBBON · GLOWS PINK

Now for the bill with the most going on, and the one this collection of charts actually gets right.

The $100 is the only US bill with a genuine 3D Security Ribbon, a blue ribbon that’s physically woven into the paper rather than printed on top of it. Tilt the note back and forth and the tiny bells and “100”s printed along the ribbon appear to slide side to side. Tilt it the other way and they shift up and down instead. It’s a real, physical, difficult to fake feature, and honestly one of the more impressive pieces of currency engineering out there.

There’s color-shifting ink in two places on this note: the large “100” in the corner shifts copper to green, and there’s a small bell resting inside a copper inkwell near Franklin’s portrait that shifts color too. Franklin’s watermark sits in the blank space to the right of his portrait, and microprinting reading “USA100” runs along his collar in precise, tiny text.

Because the $100 carries both the highest value and the most security tech, it’s the bill most worth a second look if something feels off. A hundred that feels smooth, prints flat, or shows no ribbon movement when tilted deserves a closer inspection before you accept it. That quick feel-tilt-check sequence is really the whole answer to how to tell if a $100 bill is real, and it takes about five seconds once you’ve done it a couple of times. Worth having down cold if you’re headed to the US yourself — it pairs well with getting the rest of your trip money sorted before you fly.

REFERENCE: Real vs. fake $100 bill, front and back

If there’s one detail worth actually memorizing, it’s this one, since it’s also the detail that gets mixed up most across the charts above. Here’s the real breakdown, cross-checked against Secret Service and Treasury reference material.

 

Denomination	UV Thread Color
$5	Blue
$10	Orange
$20	Green
$50	Yellow
$100	Pink
$1 / $2	No thread, no glow

$1 and $2 bills don’t glow at all under UV, because there’s no thread inside them to react to the light.

A basic UV flashlight costs about as much as lunch, and if you handle cash often, it’s a genuinely useful thing to keep near the register. Just don’t treat it as foolproof on its own. Sophisticated counterfeiters sometimes “wash” a real, lower-value bill and reprint a higher denomination on top of the original paper, which means a genuine thread can pass a UV check while everything printed over it is fake. That’s why the paper texture, portrait sharpness, and color-shifting ink checks still matter, even if you own a blacklight.

The other cheap option cashiers reach for is a counterfeit detection pen, the iodine-based markers sold at every register-supply shop. They react with the starch in ordinary wood-pulp paper and leave a dark streak, while genuine US currency, printed on cotton-linen stock with no starch in it, stays a light gold. That makes the pen a fast first pass on a stack of bills, but it only tests the paper, not the printing, so a bill that’s been bleached and reprinted on real currency stock can still pass. Use it the same way as the UV light: a quick screen, not the final word.

Say you’re holding a bill you’re fairly sure is counterfeit. What now?

First, don’t try to spend it, and if you’re a business, don’t try to just hand it back across the counter to whoever gave it to you and call it even. Once a counterfeit note has been accepted, that money is effectively gone. Banks won’t reimburse you for it. There’s no insurance policy that covers “accidentally accepted fake money.” It’s a straight loss, which is exactly why catching it before a transaction finishes matters so much more than catching it after.

If you’re a private individual holding a suspected fake, don’t try to pass it along to someone else either. Knowingly doing that is a federal crime, regardless of how the bill ended up in your hands. Contact your local police department, who can loop in the Secret Service if needed, since they’re the federal agency actually responsible for currency investigations. Try to remember whatever details you can about who gave it to you: a physical description, a receipt, security footage if you have it.

Handle the bill as little as possible after that, and keep it separate from the rest of your cash so it doesn’t accidentally end up back in circulation. It might feel like overkill for a single $20 bill, but individual counterfeit notes sometimes trace back to larger operations, and small details end up mattering more than people expect.

Does every US bill have the same security features?

No. Security features scale with the denomination. The $1 bill has no watermark, no security thread, and no color-shifting ink at all. Full security features start at the $10 bill, and the woven 3D ribbon exists only on the $100.

What color does each bill’s UV security thread glow?

$5 glows blue, $10 glows orange, $20 glows green, $50 glows yellow, and $100 glows pink. The $1 and $2 bills have no thread at all, so they don’t glow under UV light.

Is a UV light or counterfeit-detection pen enough on its own to confirm a bill is real?

No. Both are useful first screens, but neither is foolproof alone. Counterfeiters sometimes bleach a real, lower-value bill and reprint a higher denomination on the original paper, so a genuine thread can still pass a UV check even though the printing on top is fake. A detection pen only tests the paper’s starch content, not the printing. Pair either check with a look at paper texture, portrait sharpness, and color-shifting ink.

Which US bill gets counterfeited the most?

The $20 bill. It’s common enough that cashiers rarely scrutinize it the way they might a $100, but valuable enough to be worth faking — which the Secret Service names as the single most counterfeited denomination in the country.

Does the $50 bill have a 3D security ribbon?

No, and that’s a common mix-up in popular “real vs. fake” cheat sheets. The $50 has a straight embedded security thread, the same style used on the $5, $10, and $20 notes. The woven, moving 3D ribbon effect is unique to the $100 and doesn’t appear on any other US bill.

What should I do if I think I’m holding a counterfeit bill?

Don’t try to spend it or pass it to someone else — knowingly doing that is a federal crime. Contact your local police department, who can loop in the Secret Service, and hold onto any details you remember about who gave it to you. Handle the bill as little as possible and keep it separate from your other cash so it doesn’t re-enter circulation.

Spotting a fake bill was never really about becoming a forensic examiner. It’s about knowing a handful of specific, physical details for whichever bill happens to be in your hand, and not assuming every denomination plays by the same rules. A $1 note and a $100 note share a country and a currency. They don’t share a rulebook.

If you can, keep a real bill of each denomination on hand, maybe straight out of your own wallet, and actually compare it side by side against anything that looks off. Your fingers and your eyes, once trained on the real thing, will catch more than you’d think. And if you’re ever genuinely unsure about a bill in your hand, there’s no shame in just declining the transaction. That’s what the professionals recommend too.