Last updated: September 2026

What counts as a banknote error?

A banknote error is a production fault created inside the printing works and released without being caught. That definition does two jobs. It includes anything the press did wrong, from an upside-down back to a missing serial number. And it excludes everything that happened to the note after it left the building, which is where most hopeful finds turn out to belong.

The distinction matters because the two look similar to a beginner and nothing alike to a grader. A note with ink on it may have an ink smear from the press or a stain from a pen. A note with an odd margin may be a genuine cutting error or a note someone trimmed. A note missing part of its design may have an insufficient-inking error or a patch of surface lifted off by tape. In each pair the first is a collectible and the second is damage.

Errors are also not varieties. A variety is a repeatable difference built into a plate or a design, reproduced on every note printed from it. An error is a one-off or short-run accident. The Bureau of Engraving and Printing, which produces United States currency notes for the Federal Reserve System, frames its mission around manufacturing and document security (Bureau of Engraving and Printing). That is why errors are scarce: the system exists to stop them.

How do errors happen at each stage of the press?

Modern currency goes through three distinct printing stages, and every error type can be placed at one of them. For $20 Federal Reserve Notes, the Bureau of Engraving and Printing prints sheets of 32 notes: first an intaglio print of the back from engraved plates under high pressure, then a rest of several days to dry, then an intaglio print of the face, then several more drying days, then a letterpress overprint carrying the serial numbers, the Treasury Seal and the Federal Reserve System Seal with district overprint (PMG, reported by CoinWeek).

That sequence is diagnostic. If a foreign object sits under the overprint but over the face design, it arrived between the second and third stages. If the back is inverted relative to the face, the sheet went into the second press turned around. If the serial numbers are missing but the face and back are perfect, only the third stage failed. Our reference on how banknotes are printed covers intaglio, offset and letterpress in full.

What COPE and LEPE do, and why it matters for errors

The third stage in the United States is not just a press. Since the early 1970s the BEP has used COPE, the Currency Overprinting and Processing Equipment, which overprints serial numbers and seals, cuts the sheets into notes, replaces defective notes with star notes drawn from a previously printed supply, and bands the notes into packs of 100, all in one automated pass. Before COPE these were separate steps, and finished notes received a more thorough inspection after cutting. All currency was processed on COPE from late 1979 (USPaperMoney.Info).

COPE's successor, LEPE, the Large Examining and Printing Equipment, began overprinting some $1 notes at the Fort Worth facility in late 2012 and at Washington, DC in early 2014. COPE handles sheets of 32 notes; LEPE handles 32-subject sheets or the larger 50-subject sheets, and every note from a 50-subject sheet is overprinted on LEPE. Notes from 50-subject sheets can be told apart by their plate position indicator, where the letter and number are the same size instead of a large letter with a small number (USPaperMoney.Info).

Two consequences follow for collectors. First, the same machine that overprints also inspects and replaces, so third-stage errors that survive had to defeat an automated check, not a tired human. Second, the relationship between a serial number and a plate position is fixed by the equipment, which is how a specialist can work out whether a given note is even possible as described.

Every banknote error type, and what each is worth

Banknote errors fall into four families: printing errors, ink errors, overprint errors and paper or cutting errors. The table below names each type, places it at the press stage that caused it, explains why survivors are scarce, and describes where the value sits. Dollar figures are given only where a dated, attributed sale exists.

Rarity ratings are described by mechanism rather than by invented survival counts. The only published rarity rating cited here is Sullivan's R9 for retained obstructions, as reported by PMG. The only dollar figure is an attributed, dated auction result. Anyone quoting precise price tables for every error type is estimating, and error prices swing hard on how dramatic the individual note looks.

What is the most valuable error note ever sold?

The most valuable error banknote ever sold is the Del Monte Note, a $20 bill that realized $396,000 at a Heritage Auctions currency sale on 22 January 2021. Guinness World Records recognizes the result as the most expensive error note, and classifies the fault as a retained obstruction: a foreign object stuck to the paper during printing and still attached when the note entered circulation.

The note's market history shows how much an error can appreciate once it becomes famous. PMG's account, citing a Numismatic News report from August 2003, says an Ohio college student received the note in an ATM withdrawal and sold it the same year on an online marketplace for $10,000, after which it realized $25,000 at a Heritage sale in January 2006. Heritage's own 2021 announcement dates the discovery to the summer of 2004 and gives the 2006 result as $25,300 (Heritage Auctions, reported by CoinWeek). The two accounts differ on the discovery year and on a few hundred dollars in 2006; both agree on the 2021 figure. Where sources conflict, we print both rather than pick.

Heritage also noted that other objects have been printed onto US notes the same way, including a bandage, paper fragments, tape and wood shavings.

How do serial number errors happen?

Serial number errors happen at the overprinting stage, which is mechanically separate from the two intaglio printings, and they come in three shapes: a wrong character on a numbering wheel, a wheel that fails to advance, and an overprint applied upside down or out of position. All three can run for a while before anyone notices, because the fault is small and repeats identically.

The best-documented example in US currency is the inverted W. On the Series 1957 $1 silver certificate M..A block, one of the serialling presses was set up with an upside-down letter W in place of one of the prefix letter M positions. The difference is visible in the letter's sides: a normal M has vertical sides, an inverted W has sloping ones. The error appears in plate position E2 or E4, and because more than one overprinting press was running, not every note from those positions carries it. A counterpart inverted M error exists in Series 1935F (USPaperMoney.Info).

The scale of the detective work is the interesting part. The published survey breaks the block into 312 serial ranges and asks collectors to report which contain the error. As of its 15 September 2018 update, 32 ranges were confirmed as error ranges, 150 as normal, and 130 remained undetermined. That is what a genuinely open numismatic question looks like: a table of ranges, most of them still blank.

Serial numbers also drive a separate collecting field that is not about errors at all. Low numbers, repeaters, ladders and solids are deliberate outputs of a correctly working press, and they trade on pattern rather than fault. Our guide to fancy serial numbers covers those, and the two markets often overlap in the same auction.

Are star notes error notes?

No. A star note is the opposite of an error note: it is the correctly printed replacement that the system substituted when a defective note was found. Guinness World Records describes a replacement note as paper currency printed to replace an error or damaged note discovered before the currency left the control of the issuing government (Guinness World Records).

That substitution is built into the machinery described above: COPE pulls the defective note and inserts a star note from a previously printed supply during the same automated pass. So a star note is evidence that an error was caught, and an error note is evidence that one was not. Collectors chase both, for opposite reasons, and our reference on star notes and replacement notes explains how different countries mark them.

The category has its own record. The largest collection of replacement banknotes verified by Guinness is 25,500 notes, assembled by Murali Pollachi Vaidyanath of India and verified on 28 September 2020, displayed across 255 sheets of 100 unique replacement notes each.

How do you tell a real error from damage or an alteration?

Work backwards from the press. A genuine error has to be physically consistent with a stage of production, and a post-print alteration usually is not. Four checks catch most of what circulates as error material.

• Check the layering. Ink applied at the third stage sits on top of second-stage ink. If a serial number prints over an obstruction, the obstruction arrived first. If an obstruction sits over the serial number, it arrived after the note was finished, which makes it damage.
• Check the paper edges. A cutting error leaves clean machine-cut edges even when the design is out of register. A trimmed note has edges that are too smooth, margins that are too narrow, or a note that measures short against its issue's standard size.
• Check whether the fault is repeatable. Solvent-lifted ink, bleached areas and pen removal leave disturbed paper fibers and altered surface texture that no press produces. Hold the note at a raking angle to light and compare the suspect area with the rest of the surface.
• Check the serial against the plate position. On US notes the equipment fixes the relationship between serial number and plate position, and the published arithmetic for COPE and LEPE lets a specialist test whether a described note is even possible (USPaperMoney.Info).

The practical rule for buyers: above pocket-change money, buy the error certified. The difference between an error and damage is a question about manufacturing history, not about how the note looks.

How do PMG and PCGS grade error notes?

PMG and PCGS both grade banknotes on the same 1 to 70 numerical scale used for the rest of paper money. PMG records the error as a separate notation on the label: the Del Monte Note is graded PMG 64 Choice Uncirculated EPQ and noted as an Obstructed Printing Error with Retained Obstruction. The grade describes preservation; the notation describes the fault.

Two PMG designations matter most when buying errors. EPQ, Exceptional Paper Quality, means graders judged the note completely original, with no physical, chemical or material processing applied to give the appearance of a higher grade; all notes graded Very Fine 20 and higher are evaluated for it. NET is the opposite signal, applied to notes with major problems, and PMG notes that most pieces grading below Good 4 are net graded (PMG).

PCGS Banknote uses the same 1 to 70 scale and its own originality designation, PPQ, or Premium Paper Quality. For an error note, that originality call carries extra weight. An error's whole claim is that the note left the press this way, so proof that nobody has worked on the paper since is part of the evidence, not just a condition bonus. PMG also distinguishes these grade-modifying designations from its release designations such as Early Releases and First Releases, which record when a note was submitted rather than anything about the note itself (PMG). Our banknote grading guide walks the full scale, and Planet Banknote lists certified material in its graded banknotes collection.

What actually drives the value of an error note?

Five things, in roughly this order: how dramatic the error looks, how rare that type is, the grade and originality of the paper, whether it is certified, and how well known the individual note is. Notice what is not on that list: face value. A $1 note with a spectacular error outruns a $100 note with a subtle one every time.

Drama is first because error collecting is visual. An inverted back, a missing third print or a note showing half of its neighbor reads instantly across a room. A two-millimeter cutting shift does not, though both are genuine production faults. This is why the value column above is written as behavior rather than as numbers: one error type spans a wide band depending on how obvious the individual example is.

Fame compounds all of it. The Del Monte Note moved from $10,000 to $25,000 to $396,000 across three public sales in 18 years, and very little of that came from the note changing. What changed was that a generation of collectors learned its name. That is the honest reason to be cautious with any published price list for errors: the market prices specific notes, not categories.

Planet Banknote is a family-owned dealership in Sarasota, Florida, founded in 2021. Every note is sourced direct from mints, central banks, and authorized distributors, inspected through our Planet Banknote Verified process, and ships with a free Certificate of Authenticity. US orders ship free via USPS Priority, and every order includes a free bonus gift.