How to Tell if a Dollar Bill Is Fake

The three-second check: feel, tilt, check

This is the sequence cash handlers are trained on, and it catches the large majority of counterfeits without a single tool.

1. Feel the paper and the print. US currency is not paper in the ordinary sense — it is a blend of roughly 75% cotton and 25% linen, which is why a genuine note survives a washing machine. It should feel crisp and slightly textured, never slick or waxy. Run a fingernail across the portrait's shoulder and the Treasury seal: the intaglio printing process leaves ink standing proud of the surface, and you can feel it. Inkjet and laser counterfeits are flat.
2. Tilt the note. On $10 notes and higher, the numeral in the lower right corner of the face is printed in colour-shifting ink. Tilt the note back and forth and it moves between copper and green. The shift is obvious once you have seen it — if the numeral stays one colour at every angle, stop there.
3. Check against light. Hold the note up to any light source. On $5 notes and higher you will see a watermark in the blank space, and a vertical security thread embedded in the paper with the denomination spelled out along it. Both are inside the paper, not printed on it, and both are visible from either side.

Security features by denomination

Features differ substantially between denominations, and this is where most people go wrong — expecting a watermark on a $1 note, or colour-shifting ink on a $5. Neither exists.

Two things follow from that table. First, the $1 and $2 have no watermark, thread or colour-shifting ink at all — for those denominations the only checks available are the paper, the raised print, the fine-line engraving and the embedded red and blue fibres. Second, the UV colours are denomination-specific, which is what makes a UV light useful: a bleached lower-denomination note reprinted as a $100 will still glow the colour of the original denomination.

The $100 note in detail

The current $100 design carries the most advanced feature set of any US note, and it is worth knowing properly because the $100 is the denomination counterfeiters target most.

• The 3D security ribbon. A blue ribbon woven into the paper, not printed on it, running vertically to the right of the portrait. Tilt the note and the bells and 100s inside it appear to move — side to side when you tilt up and down, and up and down when you tilt side to side. Nothing about this can be reproduced by printing, which makes it the single strongest check on the note.
• The bell in the inkwell. A colour-shifting copper inkwell to the right of the portrait containing a bell. Tilt the note and the bell shifts from copper to green, appearing and disappearing against the inkwell.
• Watermark and thread. A Franklin portrait watermark right of the main portrait, and a security thread to the left reading "USA 100", glowing pink under UV.
• Microprinting. Tiny text on the collar of Franklin's jacket, around the blank space containing the watermark, along the quill, and in the borders. Under magnification it should be sharp and legible; on counterfeits it is typically a grey blur.
• Raised printing. Run a fingernail down Franklin's shoulder. The texture should be pronounced.

Older $100 notes without the blue ribbon are still legal tender and still perfectly valid — they simply predate the current design. They carry the watermark, thread, colour-shifting numeral and microprinting, but not the ribbon or the inkwell bell.

Checks that apply to every note

• The serial numbers must match. The serial appears twice on the face, and the two printings are always identical on a genuine note. Mismatched serials mean the note has been altered. Our serial number checker covers how serials are structured.
• The portrait should stand out from the background. On genuine notes the portrait has depth and lifelike detail, and the fine lines in the background are sharp and unbroken. Counterfeit portraits tend to look flat, dark and slightly muddy, and the background lines blur together.
• Border lines should be crisp. The fine scrollwork around the edge of the note should be clear and continuous. Broken or smudged border lines are a common tell.
• The Federal Reserve and Treasury seals should be sharp. The sawtooth points on the seals should be distinct and even, not blunt or uneven.
• Red and blue fibres are embedded, not printed. Genuine paper has tiny red and blue synthetic fibres running through it in random directions. On a counterfeit they are often printed onto the surface — under a loupe you can see they sit on top of the paper rather than inside it.
• Size. Every US note, every denomination, measures 6.14 inches by 2.61 inches (156 mm by 66.3 mm). A note that is visibly a different size from another note is a serious problem.

Why counterfeit detection pens are not enough

The iodine pens used at retail counters test for one thing: starch. Ordinary wood-pulp paper contains starch and turns the ink dark; genuine currency paper does not, so the mark stays amber. That works against a note printed on paper from an office supply store, which is the most common amateur counterfeit.

It fails in two situations that matter. A "bleached" or "washed" note — a genuine low-denomination bill chemically stripped and reprinted as a higher denomination — is on real currency paper, so it passes the pen every time. And counterfeiters using starch-free stock also pass. This is why a pen should never be the only check: it says something about the paper and nothing about the watermark, thread or colour-shifting ink.

If you think you have a counterfeit note

Handling this correctly matters, both legally and practically.

1. Do not return it to the person who gave it to you. Passing a note you know to be counterfeit is itself an offence, and returning it destroys any chance of the case going anywhere.
2. Delay the person if you can do so safely. Note a description, and vehicle details if relevant. Never put yourself at risk over a banknote.
3. Handle the note as little as possible. Put it in an envelope or a sleeve. Do not write on the note itself.
4. Contact the authorities. In the United States, counterfeit currency is investigated by the US Secret Service. Contact your local police department or the nearest Secret Service field office and surrender the note to them.
5. Expect no reimbursement. This is the hard part: a counterfeit note is worthless, and whoever is holding it when it is identified absorbs the loss. There is no compensation scheme. That is the entire reason the three-second check is worth learning.

If you have a note that is genuine but badly damaged rather than counterfeit, that is a completely different process with a much better outcome — see the mutilated currency guide.

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