Skip to main content

What Do The Letters Stand For In The Serial Number?

by
Last updated on 9 min read

In 2026, the first letter in a U.S. bill’s serial number indicates the series year (D=2026), the second letter identifies the Federal Reserve Bank (A=Boston, B=New York, etc.), and the remaining digits are a sequential production number.

What do the letters in the serial number represent?

The first letter shows the series year (D=2026), the second letter identifies the Federal Reserve Bank, and the remaining digits are a sequential production number.

If your U.S. bill’s serial number looks like a cryptic string instead of a simple label, you’re not alone. The letters and digits aren’t random—they’re a built-in tracking system the Bureau of Engraving and Printing has refined over decades. Here’s how to read them and what they mean in 2026.

Quick Fix Summary: The first letter shows the series year, the second letter identifies the Federal Reserve Bank (for $5 and higher), and the rest is a sequential run number. On $1 and $2 bills, only the Fed letter appears. Plate numbers on the face/back tell which printing plates produced the note.

What does each part of the serial number indicate?

The first letter corresponds to the series year (D=2026), the second letter identifies the issuing Federal Reserve Bank, and the remaining nine digits are a sequential production number.

Each U.S. Federal Reserve note carries an 11-character serial number printed twice on the front. The first letter corresponds to the series year (A=2023, B=2024, C=2025, D=2026, etc.). The second letter identifies the issuing Federal Reserve Bank (A=Boston, B=New York, C=Philadelphia, D=Cleveland, etc.). The remaining nine characters are a sequential production number that grew from seven digits before December 2007 to eight digits afterward.

According to the Federal Reserve, this system ensures consistent tracking across all 12 Federal Reserve districts.

How do you read a serial number on a bill?

To read a serial number, locate it on the front of the bill, identify the first letter for the series year, the second letter for the Federal Reserve Bank, and the remaining digits for the sequential production number.

  1. First, find the serial number on the front of the bill. It shows up twice—once near the top right corner and again at the bottom left.
  2. Look at the first letter. Right now in 2026, A means the bill was printed in 2023, B for 2024, C for 2025, and D for 2026. The system just moves one letter forward each year.
  3. Check the second letter. That’s the Federal Reserve Bank code. A is Boston, B is New York, C is Philadelphia, and so on through L for San Francisco.
  4. Flip the bill over. You’ll see two six-digit plate numbers—one near the left edge on the front, one on the back. These identify the exact printing plates used for each side.
  5. Finally, the remaining digits run in sequence from 00000001 to 99999999 (or 000000001 to 999999999 after 2007). Large sheets of bills get printed at once, so you might also see position letters like B3 to show where the note sat on the plate.

What should you do if a serial number is unclear?

If the serial number is unclear, check for star notes, ladder/radar patterns, or Fed district numbers on $1 and $2 bills.

  • Star notes: Bills ending with a star (like AB1234567*) are replacement notes printed when a regular sheet had a defect. They’re fairly common but collectible; most sell for $3–$20, while rare duplicates can hit $100 or more.
  • Ladder and radar bills: Serials that climb up (12345678) or drop down (87654321) or read the same backward (like 123321AB) are gold for collectors. Perfect patterns command serious premiums.
  • Fed district number on $1 and $2: These small bills skip the series year letter. Instead, a tiny number in all four corners—1 through 12—tells you which Federal Reserve Bank issued it (1=Boston, 2=New York, etc.).

The U.S. Department of the Treasury confirms that star notes are produced to maintain consistent supply during high-volume printing runs.

How can you keep bills in good condition?

To keep bills in good shape, handle them by the edges, store star notes in sleeves, and check serials before large cash deposits.

ActionWhy It Matters
Handle bills by the edgesAvoid smudging ink around serials, which can blur the characters collectors rely on.
Store star notes in sleevesLimiting exposure to moisture and light preserves the paper finish and color.
Check serials before large cash depositsBanks and ATMs log serial numbers during sorting; keeping serials legible helps resolve disputes.
Note plate numbers only if inspecting quality control issuesPlate numbers are internal records, not public tracking tools, so they’re mainly useful for authentication.

Serial numbers are meant for internal tracking, not personal privacy. Since the mid-2010s, high-speed currency processing machines at the Federal Reserve have logged serials for supply-chain analytics, not surveillance. The numbers help estimate note lifespan—Federal Reserve data from 2024 shows a $5 bill averages just 6.5 months in circulation before replacement.

For collectors, legibility is everything: faded ink or torn corners kill potential premiums even if the pattern would otherwise be rare. Always double-check that the series year letter matches the actual date printed on the bill.

The Federal Reserve Bank of San Francisco notes that the second letter (B = New York) accounts for roughly 20% of all notes printed as of 2025 due to the district’s high-volume production capacity.

What do Face and Back Plate Numbers indicate?

Face and Back Plate Numbers identify where your money is printed.

Face and Back Plate Numbers. The face plate and back plate numbers identify the printing plates used to print each side of the note. The face plate number is found on the face of the note and the back plate number is found on the back.

How much is a $1 star note worth?

A normal $1 star note sells for about $3, but duplicate print run star notes typically sell for $15–$20.

In fact, while a normal $1 star note sells for about $3, a duplicate print run star note typically sells for $15 – $20. There is a situation, however, where these bills can be worth much more than that. Only a few pairs of the same serial numbers have been put together.

What does the note position letter and number mean?

The note position letter and number (like B3) shows where the bill was printed on the plate.

The note position letter and number is a combination of one letter and one number (on this bill it’s B3) and simply denotes what position on the plate the bill was printed. The front of the $1 bill also includes its note position and plate serial number (B95).

What do the first two characters of the serial number show?

The first two characters show the year and month, while the rest is a sequential production number.

The first two characters of the serial number represent the year and month of manufacture. The remainder of the serial is a sequential production number, seven digits in length before December 2007 (DM), and eight digits in length after.

Why are ladder bills popular among collectors?

Ladder bills with ascending or descending serial numbers are sought-after by collectors.

Notes that have serial numbers with digits that ascend or descend are pretty prized. Called ladder bills, the most sought-after are the true or perfect ladder serial numbers 12345678 and 87654321. They are exceedingly scarce and represent only one in 96 million bills printed, hence their high value.

Do banks track serial numbers?

ATMs and cash counting machines record serial numbers, but banks don’t actively track them.

Not only ATMs are recording serial numbers. So are cash counting and sorting machines. Banks would start tracking notes if they had some reason to, but they don’t. ... Bank note serial numbers are used today, to estimate the average lifespan of a note (a 5 pound note has around a 6 month lifespan on average IIRC).

Where can you find the serial number on an Android tablet?

You can find the serial number in your Android tablet’s Settings menu.

Android tablet Settings feature

Option one: Open Settings > About Tablet > Status > Serial Number.

What is a mint?

A mint is an industrial facility that manufactures coins used as currency.

A mint is an industrial facility which manufactures coins that can be used as currency.

What do the first two characters of a redesigned note's serial number show?

An 11-character serial number appears twice on redesigned notes, with the first letter showing the series year and the second showing the Federal Reserve Bank.

Serial number

A unique combination of 11 numbers and letters appears twice on the front of each redesigned note. The first letter of the serial number corresponds to the series year (see chart). The second prefix letter identifies the Federal Reserve Bank that issued the note.

What do the numbers on a $2 bill refer to?

The numbers on a 2 dollar bill refer to the Federal Reserve district that printed it.

Symbol: Federal reserve district number

On the front of the dollar bill, a one- or two-digit number appears four times. This number refers to the Federal Reserve Bank that printed the bill. A “1,” for instance, would mean it was made in Boston, while “2” refers to New York.

Why are palindromes and repeated serial numbers valuable on $2 bills?

Palindromes and repeated serial numbers make 2 dollar bills more valuable.

  1. Palindromes – Also called “radar notes,” these serial numbers read the same whether you look at them backwards or forwards.
  2. Repeated numbers – If the serial number repeats, this is rare and more valuable.

What is a serial number?

A serial number is a unique identifier used for identification and inventory purposes.

Sometimes abbreviated as Serial No., SN, or S/N, a serial number is a unique number used for identification and inventory purposes. ... Pictured is an example of what a serial number may look like on the back or side of a computer.

What information do serial numbers reveal?

Serial numbers reveal manufacturing details like origin and production date.

Manufacturers can use serial numbers to see where a device came from and when it was manufactured, so serial numbers can help identify if there’s a problem somewhere in the manufacturing process. Manufacturers wouldn’t be able to track individual devices without some sort of unique identifier.

Why are serial numbers important for identification?

Serial numbers uniquely identify identical units and help prevent theft and counterfeiting.

Serial numbers identify otherwise identical individual units with many obvious uses. Serial numbers are a deterrent against theft and counterfeit products, as they can be recorded, and stolen or otherwise irregular goods can be identified. Some items with serial numbers are automobiles, electronics, and appliances.

Edited and fact-checked by the TechFactsHub editorial team.
Alex Chen

Alex Chen is a senior tech writer and former IT support specialist with over a decade of experience troubleshooting everything from blue screens to printer jams. He lives in Portland, OR, where he spends his free time building custom PCs and wondering why printer drivers still don't work in 2026.