Short answer: a counterfeit pen, also called a counterfeit marker or money checker pen, tests a bill in seconds: mark a light, unprinted spot on the note and watch the color. Carousel Checks sells D-TEK Counterfeit Detector Pens at $5.59 for a 3-pack and $16.86 for a box of 12, about $1.41 a pen. Confirm any suspect note with the security features the U.S. Currency Education Program lists, shown below. Prices checked October 20, 2026.
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What a counterfeit pen is
A counterfeit pen is a marker filled with a test ink instead of writing ink. You draw a short line or a small cross on the bill, and the color of the mark tells you whether the paper reacts like genuine currency paper. Many stores keep one at the register, and anyone who takes cash at a yard sale, a fundraiser or a rental property can use one the same way.
Carousel Checks sells D-TEK pens in its fraud prevention section, next to its security stamps and RFID card sleeves. Carousel describes them like this:
- D-TEK Counterfeit Pens allow you to detect counterfeit currency in seconds.
- The box of 12 lists four highlights: highly effective, quick and simple, works on international and US currency, and antimicrobial protection.
- Both packs are PROP 65 compliant.
Searchers also call these money pens, fake money pens and counterfeit money markers. They are all the same tool: a marker you use on paper money, not on checks.
Counterfeit pen prices
Counterfeit detector pens sold by the check printers we cover, checked October 20, 2026:
| Pack | Seller | Price | Per pen |
|---|---|---|---|
| D-TEK Counterfeit Detector Pen, 3/Pack | Carousel Checks | $5.59 | about $1.86 |
| D-TEK Counterfeit Detector Pen, 12/Box | Carousel Checks | $16.86 | about $1.41 |
The box of 12 costs about 45 cents less per pen than the 3-pack. Plan on one pen per cash drawer plus a spare, so a store with four registers buys the box. A household or a church treasurer needs the 3-pack.
Checks Unlimited and Bank Checks Plus do not list counterfeit pens. Carousel is the only one of our three check printers that sells them, and it ships them with the rest of an order, so you can add a pack to an order of business checks or deposit bags.
How to use a counterfeit pen
Carousel gives a short method on both product pages. Here it is step by step:
- Find an area of the note that is lightly colored and not printed on, such as the blank space beside the portrait.
- Uncap the pen and mark the note with a small cross or a short line. Press lightly; the ink only needs to touch the paper.
- Read the color right away, then look again a few seconds later.
- A bright yellow or amber mark means the note is valid.
- A mark that goes dark and stays dark means the note is forged.
Recap the pen after every use so the tip does not dry out, and keep it at the register, not in a drawer across the room. A pen that is hard to reach is a pen nobody uses on a busy day.
Reading the mark: yellow or dark
| What you see | What it means | What to do |
|---|---|---|
| Bright yellow or amber mark | Carousel: the note is valid | Accept the bill |
| Dark mark that stays dark | Carousel: the note is forged | Keep the bill and check the security features below |
| A mark you cannot read clearly | Not a result yet | Mark a different blank area, then check the features |
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Confirm the note: 6 security features
A pen gives a fast first answer. Before you refuse or report a bill, check the note itself. The U.S. Currency Education Program lists these features for the $100 note:
- Security thread: hold the note to light to see an embedded thread to the left of the portrait, printed with USA and 100. It glows pink under ultraviolet light.
- 3-D Security Ribbon: tilt the note and the bells on the blue ribbon change to 100s as they move. The ribbon is woven into the paper, not printed on it.
- Bell in the inkwell: tilt the note to see the bell in the copper inkwell change from copper to green.
- Watermark: hold the note to light for a faint image of Benjamin Franklin in the blank space to the right of the portrait, visible from both sides.
- Color-shifting ink: the numeral 100 in the lower right corner shifts from copper to green.
- Raised printing: move a finger along Franklin’s shoulder; it feels rough to the touch.
The same source says Federal Reserve note paper is one-fourth linen and three-fourths cotton, with red and blue security fibers. For a $20 or a $50, open the page for that denomination on the same site; each note has its own list.
Counterfeit money detector lamps shine ultraviolet light, the light that makes the $100 security thread glow pink. None of our three check printers sells a lamp or a machine; the pen plus the tilt, light and touch checks above need no extra equipment.
Who keeps a counterfeit pen
- Shops, restaurants and salons: one pen at each register for $20, $50 and $100 bills.
- Landlords and property managers who accept cash rent.
- Churches, clubs and schools counting collections, dues and fundraiser cash.
- Yard sale and marketplace sellers taking large bills from strangers.
- Anyone preparing a bank deposit, so a fake bill is caught before the bank finds it.
If you find a counterfeit bill
The U.S. Secret Service says individuals submit suspected counterfeit currency to their local police department, and that a local bank can also help identify counterfeit currency. Police departments, banks and cash processors then send suspected notes to the Secret Service.
- Do not hand the bill back to the person who gave it to you.
- Note who passed it and when, while the details are fresh.
- Handle the bill as little as possible and put it in an envelope.
- Contact your local police department, or ask your bank to look at it.
Pens, bands and deposit bags
A counterfeit pen is one step of a cash routine. Band bills with color-coded money bands, roll coins in coin wrappers, and carry the deposit in a tamper-evident deposit bag. Carousel sells all three, so one order covers the whole drawer. For checks you write, the matching tool is a check writing pen with Super Ink.
How to order and delivery
- Pick the pack: 3 pens for $5.59 or 12 for $16.86.
- Add money bands, coin wrappers or deposit bags if you need them.
- Choose delivery and pay.
Delivery: Carousel Checks lists Next Day Air (1 to 2 business days), 2nd Day Air (2 to 3), Ground (2 to 5), Trackable (3 to 7), USPS Priority (7 to 10) and Bulk (9 to 18 business days), plus processing time.
Ordering checks too? Checks Unlimited sells Blue Classic checks at $23.49 for 80 and Carousel sells Blue Safety checks at $20.00 a box. Checks Unlimited sells MLB checks for 30 clubs, from the Yankees and Red Sox to the Dodgers and Cubs, and collegiate checks for 19 schools, including Alabama, Auburn, Clemson, Georgia, LSU, Notre Dame, Penn State and Tennessee.
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Counterfeit pens: frequently asked questions
Where can I buy a counterfeit pen?
Carousel Checks sells D-TEK Counterfeit Detector Pens online: $5.59 for a 3-pack and $16.86 for a box of 12 (October 20, 2026). Checks Unlimited and Bank Checks Plus do not list them.
How do you use a counterfeit money pen?
Mark a lightly colored area of the note that is not printed on, for example with a small cross, and read the color of the mark.
What color should a counterfeit pen mark be on a real bill?
Carousel says a bright yellow or amber mark means the note is valid, and a mark that goes dark and stays dark means the note is forged.
How much does a counterfeit pen cost?
At Carousel a 3-pack of D-TEK pens costs $5.59, about $1.86 a pen, and a box of 12 costs $16.86, about $1.41 a pen.
Do counterfeit pens work on all bills?
Carousel says D-TEK pens work on international and US currency. Confirm a suspect note with the security thread, watermark and color-shifting ink as well.
What should I do with a counterfeit bill?
The U.S. Secret Service says individuals submit suspected counterfeit currency to their local police department, and a local bank can help identify it.
Related guides
- Money bands
- Bank deposit bags
- Coin wrappers
- Check writing pens
- Business checks
- Check accessories
- How to reorder checks online
- Cheapest checks 2026
- Check companies compared
Affiliate disclosure: GetBankChecks.com is an independent guide, not a check printer. Some links are affiliate links, and we earn a commission if you buy through them, at no extra cost to you. Prices, codes and designs change, so check them on the merchant’s site before you pay.