Wrong Planchet (WPL)

A Wrong Planchet error occurs when a coin is struck on a planchet that was not intended for it: one meant for a different denomination, for a different country's coinage, or -- in the case of an off-metal transitional error -- for the same denomination in the composition it was being struck in the year before or the year after. The coin displays the correct die design -- the obverse and reverse are those of the intended denomination -- but the size, weight, and metal composition are those of the planchet it was actually struck on. Error-Ref's definition covers planchets meant for any other denomination, U.S. or foreign, and notes that the wrong planchet can share the coin's composition (a quarter on a dime planchet) or differ from it (a quarter on a nickel planchet). Two things went wrong: a stray planchet entered the production line, and quality control failed to catch it.

How Does It Happen?

The U.S. Mint operates multiple coining presses, often producing several denominations simultaneously within the same facility. Each denomination has its own planchet supply: bins or hoppers of blanks that are fed into the press by automated feed systems. Wrong planchet errors occur when a planchet from one denomination's supply ends up in another denomination's press.

The contamination pathways include:

• Container contamination: Planchets are moved between the blanking room and the coining presses in bins and bags. A blank left in a container that is then refilled with another denomination's planchets can reach the wrong press. CoinWeek, for example, attributes 1965 quarters on silver planchets to old blanks stuck in the tote bags used to store them.

• Shared equipment and floor space: Multiple denomination presses operate in close proximity. A planchet that bounces off one press, rolls across the floor, or is ejected from a jammed feed mechanism can end up in an adjacent press's feed system.

• Size compatibility: A stray planchet smaller than the intended one can drop into the collar and be struck. A dime planchet (17.91mm) fits a cent press (19.05mm), and a nickel planchet (21.21mm) fits a quarter press (24.26mm). A planchet larger than the collar cannot drop into it, so larger-planchet errors are struck partly or wholly outside the collar, and a planchet far too large, such as a half dollar planchet (30.61mm) in a dime press, does not get struck at all.

• Foreign planchet contamination: The U.S. Mint has historically produced coins for foreign countries on contract. When foreign planchet production runs on the same equipment as domestic production, foreign blanks can contaminate domestic hoppers. This is the origin of "wrong country" planchet errors, such as the 1941 Lincoln cent Error-Ref shows struck on a bronze Panama 1¼ centesimos planchet, from a contract the Mint struck in 1940.

Once a wrong planchet enters the press, the dies close and strike with full force. The die design is impressed onto whatever metal is present. If the planchet is smaller than the dies, the design is incomplete -- only the portion of the die that contacts the smaller planchet leaves an impression. If the planchet is the same size or larger, the full design is impressed but on the wrong metal and at the wrong weight.

How to Identify a Wrong Planchet Error

Wrong planchet errors have definitive diagnostic characteristics:

• Wrong weight: This is the primary authentication point. The coin's weight matches the planchet it was struck on, not the denomination shown in the design. A Lincoln cent design on a dime planchet weighs 2.268 grams (dime weight), not 2.5 grams (cent weight).

• Wrong diameter: The coin's physical size matches the wrong planchet. If the planchet is smaller than the intended denomination, the design is cut off at the edges -- portions of the rim, lettering, or design elements are missing because the planchet did not extend to the full die area.

• Wrong metal/color: The most visually obvious indicator. A cent design on a silver-colored clad dime planchet, or a quarter design on a copper cent planchet, shows the wrong metal for the denomination. The color mismatch is immediately apparent.

• Correct die design: Despite the wrong planchet, the design elements that are present are correct for the intended denomination. The date, mint mark, portrait, and reverse design all match the expected die pair. This distinguishes wrong planchet errors from other error types.

• Edge: Reeding is made by the collar at the moment of striking; blanks and planchets have plain edges. So the edge follows the press the coin was struck in, not the planchet. A cent on a dime planchet has a plain edge, like any cent. A planchet that does not expand to fill the collar picks up little or no reeding.

Common Wrong Planchet Combinations

Off-Metal and Transitional Planchets

The best-known wrong planchet errors in American numismatics are not cross-denomination at all. When the Mint changes the composition of a denomination, planchets of the outgoing metal remain in the bins, the hoppers and the press area for a short time, and a few get struck with the new year's dies. The design is correct, the diameter is correct, and the denomination is correct -- only the metal is a year out of date. These are called off-metal or transitional errors, and they are wrong planchet errors in the strict sense: the blank was not the one intended for that coin.

These coins are also transitional errors, and the two labels are not alternatives. "Transitional" is the larger bucket -- something from the adjacent year used when it should not have been -- and it covers the dies, the planchet, or both. A 1988 cent with the 1989 reverse is transitional and weighs exactly right, because only the design crossed the boundary. A 1943 bronze cent is transitional and weighs wrong, because the planchet crossed it. The 1965 silver dime is both at once. What a wrong planchet page can add is the part a scale settles, so that is what follows.

Weight is almost always the whole diagnosis, and for the 1943 and 1944 cents a magnet settles it before the scale comes out -- zinc-coated steel is magnetic, bronze is not.

A coin that passes the weight test still needs certification. These are among the most imitated coins in the hobby, and the usual imitation is not a counterfeit but an altered coin -- a genuine 1943 steel cent copper-plated, or a genuine 1944 bronze cent with its date reworked.

Notable Examples

1943 Bronze Cent

One of the best-known U.S. error coins. The Mint struck 1943 cents on zinc-coated steel to conserve copper for the war, but bronze planchets left over from 1942 production remained in the system and a small number were struck with 1943 dies. About two dozen are known across the three mints; one recent tally, by Saul Teichman, counts 17 from Philadelphia, 7 from San Francisco and a single 1943-D. A genuine one weighs 3.11 grams and is not attracted to a magnet; the millions of look-alikes are copper-plated steel cents, which are.

1944 Steel Cent

The mirror image, and the reason the two are always discussed together. When the Mint returned to bronze in 1944, zinc-coated steel planchets left from 1943 remained in the system and were struck with 1944 dies. A genuine example is magnetic and weighs about 2.70 grams, against 3.11 grams for the bronze cents of that year.

1966 Silver Quarter

The clad transition of 1965 produced the same error in quarters. CoinWeek describes 1965 quarters struck on leftover 1964 silver planchets and a 1967 quarter on a 90 percent silver planchet, and a clad-era quarter on a silver planchet found in a search of silver quarters was offered by Stack's Bowers in 2025 (search). A silver quarter weighs 6.25 grams against 5.67 grams for clad, and shows no copper stripe at the edge.

2000-P Sacagawea Dollar on a Ghana 100 Cedis Ring

Error-Ref shows a 2000-P Sacagawea dollar struck on the copper-nickel outer ring of a Ghana 100 cedis, a bimetallic coin. Error-Ref says the ring almost surely came from the Royal Canadian Mint, which processed Sacagawea dollar planchets for the U.S. Mint during peak demand, and it was close enough to the dollar's diameter to pass the Mint's riddlers.

Lincoln Cent on Dime Planchet

The classic U.S. wrong planchet error. Because a dime planchet (17.91mm) is only a little smaller than a cent (19.05mm), it drops easily into a cent collar. The result is an undersized Lincoln cent on a silver-colored clad planchet with a plain edge, and often a portion of the design and rim off the planchet.

Washington Quarter on Nickel Planchet

A nickel planchet (21.21mm) is smaller than a quarter (24.26mm), so it fits in the quarter collar and the coin comes out undersized, with the outer part of the design missing. It weighs 5.0 grams (nickel weight) instead of 5.67 grams (quarter weight). Quarters are clad and nickels are solid copper-nickel, so the edge shows the error: no copper core stripe is visible.

Eisenhower Dollar on Cent Planchet

An extreme size mismatch. The Eisenhower dollar design (38.1mm) struck on a cent planchet (19.05mm) produces a coin showing only the central portion of the Eisenhower portrait. The entire rim, most of the lettering, and the portrait's outer edges are absent. The examples Mike Byers has published are proof Ike dollars from San Francisco, including a centered piece, an off-center mated pair, and a 1972-S struck together with two cent planchets and a nickel planchet (search).

2000-P Sacagawea Dollar / Washington Quarter Mule

Often discussed alongside wrong planchet coins, but it is a mule: the planchet is right for one of its dies, and the dies are what is wrong. A Washington state quarter obverse was paired with a Sacagawea dollar reverse and struck on a normal dollar planchet. CoinWeek counted 19 known in 2022.

Collecting Tips

• Authentication: Altered coins are common in this category (plated cents passed off as "cents on dime planchets," filed-down coins, copper-plated 1943 steel cents). Buy certified examples from PCGS or NGC.

• Weight is the definitive test: A precision scale accurate to 0.01 grams is the most important tool for evaluating wrong planchet coins. The weight must match the alleged wrong planchet, not the denomination shown in the design. A weight that matches no U.S. planchet calls for a closer look: the coin may be altered, or struck on a foreign planchet.

• Date and mint mark: When a smaller planchet is struck by larger dies, the amount of visible design varies. A coin that still shows the full date and mint mark can be attributed precisely; one with the date off the planchet cannot.

• Size mismatch: A planchet larger than the collar cannot drop into it, so wrong planchet coins are more often struck on a smaller planchet than normal. A planchet much smaller than the dies leaves a large part of the design off the coin.

• Foreign planchets: Wrong country planchet errors depend on the Mint (or a supplier) handling foreign planchets at the same time, so they cluster around specific contracts, such as the Panama coins of 1940 or the Royal Canadian Mint's dollar planchet work in 2000.

• Check for dual errors: Some wrong planchet coins also exhibit off-center strikes, broadstrikes, or other striking errors, like the 1920 Lincoln cent Error-Ref shows broadstruck on an Argentina 10 centavos planchet.