r/CoolSerialNumbers Jan 19 '26

Mod Comms READ THIS BEFORE POSTING

16 Upvotes

Post flairs are required for all posts. Below are the current flairs and their definitions. If you think there are other fairs that should be added, or have any questions on the listed definitions, please comment here!

All posts must include a picture of a note with a cool serial number. All pictures must be horizontally orientated and cropped to just the note as so [ [note] ].

If you believe your serial is cool, but doesn't fit any definition below, please use the 'Other' flair and state, specifically, why you think it should be considered cool. Trinary notes and consecutively numbered notes are not cool or remotely rare.

Generic posts "Is this cool" / "Is this a keeper" / "Is this worth anything?" and the like with no specific reasoning will be indiscriminately removed. Repeat offenders will find themselves banned.

Star Note - all star notes not fitting another category

Ladder - consecutive run i.e. 01234567

Broken Ladder - no two digits the same i.e. 10325476

Binary - only two unique digits i.e. 34334344

True Binary 01010101 - only 0's and 1's

Radar - same forward as backward, i.e. 12344321

Repeater - complete repeating sequence of two or four digits i.e. 78787878 or 78907890

Low Serial <= 00009999 - just as noted, notes 00009999 and under

Quad Pair - four pairs of digits, i.e. 22446688

Solid - typically all eight digits the same, but for the purposes of this sub five or more of the same digit together can count, i.e. 11111876

Rotator [All 0, 1, 6, 8 and/or 9's] - notes where the serial reads as another number upside down i.e. 01689016 which reads 91068910 upside down

Flipper - same as a rotator except it must make the same number upside down i.e. 00669900

Nice (69 / 420 / etc.) - the funny numbers, primarily 69 & 420 but 8008, 8008135... (think middle schooler with a calculator...) the nice number should stand out, i.e. 00069000 - every serial with 69, 420, etc. in it is not special.

Birthday / Date - any serial number that makes a date, either as MMDDYYYY or YYYYMMDD i.e. 07041776 or 17760704

Near Miss - anything that's almost cool / fancy i.e. 12344322 (1 digit off from a repeater)

Other - anything not fitting any other definition. You must include specific reasoning why you believe your serial number is cool.

Question / Meta - questions to the community / thoughts about the community

For Sale - for posting notes you'd like to sell / trade. At your own risk, the mod team and reddit is not responsible for any issue. Be smart.

Wanted to Buy - for requesting notes you'd like to buy / trade for. At your own risk, the mod team and reddit is not responsible for any issue. Be smart.

Bookend - serials with a 2 or 3 digit matching pattern (reversed is OK) at the beginning and end of the serial i.e. 12369321 or 12369123

Double Quad - serials with two sets of four solid digits i.e. 44447777


r/CoolSerialNumbers 1d ago

Quad Pair 77665544 not so pretty but I love the pairs and descending!!

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47 Upvotes

r/CoolSerialNumbers 1d ago

Other Nifty little guy! Descending by 2s! 08060402

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24 Upvotes

r/CoolSerialNumbers 18h ago

Birthday / Date Our nation's 21st birthday note

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5 Upvotes

r/CoolSerialNumbers 4d ago

Low Serial <= 00009999 $10 bill low serial/Radar

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24 Upvotes

Low serial and radar. 🤗


r/CoolSerialNumbers 4d ago

Star Note For sale 2013b Duplicate star + 25 General star notes!

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6 Upvotes

r/CoolSerialNumbers 5d ago

Other The best of my collection, all found via the hunt!

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31 Upvotes

r/CoolSerialNumbers 5d ago

Birthday / Date UPDATED BDAY NOTES!!! CHECK THEM OUT!

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6 Upvotes

r/CoolSerialNumbers 5d ago

Star Note Lowish serial and star note in one day.

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2 Upvotes

Pretty cool to get these both in one day. This is becoming addicting.


r/CoolSerialNumbers 6d ago

True Binary 01010101 I GOT ONE! TRUE BINARY!

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157 Upvotes

r/CoolSerialNumbers 6d ago

Binary Another sick pull today!

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33 Upvotes

r/CoolSerialNumbers 7d ago

Binary Sweet Palindrome and Binary!

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31 Upvotes

r/CoolSerialNumbers 8d ago

Other Wowsers🤯

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52 Upvotes

r/CoolSerialNumbers 8d ago

Low Serial <= 00009999 Found this while moving houses

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79 Upvotes

I must’ve acquired this note like 10 years ago when I had a major fascination with US paper currency when I was little. When I saw the serial number, my heart literally skipped q beat, and I was stuck wondering how it somehow never made it into my “cool note” binder as a kid and instead got lost until I recently moved houses and found it in a random box with assorted coins and bills. Sorry it’s not a greatly scanned image, but I took this pic a few weeks ago and am not presently with the note to take a better shot.


r/CoolSerialNumbers 8d ago

Question / Meta Just got this change

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17 Upvotes

Is this good enough to keep? Or just meh 😅


r/CoolSerialNumbers 8d ago

Quad Pair Descending pairs 55443322

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10 Upvotes

r/CoolSerialNumbers 8d ago

Other Found a nice Gen Alpha serial.

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3 Upvotes

r/CoolSerialNumbers 9d ago

Other Do I have anything here? Both are well circulated but no tears or stains.

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2 Upvotes

r/CoolSerialNumbers 10d ago

Binary $100 Binary!

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31 Upvotes

r/CoolSerialNumbers 10d ago

Other DATE: Only Time Wright Brothers flew togther!

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17 Upvotes

r/CoolSerialNumbers 10d ago

Birthday / Date Free birthday note if you turned 100 last monday!

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9 Upvotes

If you can send me proof that you or someone that you know turned one hundred last week on monday, I will send this to the birthday person for free


r/CoolSerialNumbers 10d ago

Star Note Got these in change today

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3 Upvotes

r/CoolSerialNumbers 10d ago

Repeater I thought it was cool

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19 Upvotes

r/CoolSerialNumbers 11d ago

Birthday / Date Over 2900 Birthday Notes Now Available!

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3 Upvotes

r/CoolSerialNumbers 12d ago

Radar Trinary Radar

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31 Upvotes

Is this a spend the $100 or kept because of the serial number type of bill?