During World War II, the United States needed copper to make ammunition.
The Mint switched to zinc-coated steel for all pennies in 1943 to save metal for the war effort.
A few leftover bronze planchets from 1942 remained stuck inside the hopper bins at the San Francisco Mint.
Workers fed the machines steel blanks, but those stray bronze blanks slipped into the press anyway.
The dies stamped them with the 1943 date and the small "S" mint mark.
They dropped into regular circulation bags without anyone noticing the error.
Today, these wartime off-metal strikes are among the famous mistakes in all of American numismatics.
A certified example of this coin brought $504,000 in a 2020 sale held by Heritage Auctions.
The coin was certified as MS-63 Brown by professional coin graders.
The "MS" stands for Mint State, which means the coin never circulated in daily commerce.
The number 63 places it in the uncirculated range, showing light marks from handling but full original detail.
The "Brown" label describes the natural, mellowed patina the copper took on over the decades.
This particular coin once belonged to the well-known collector Bob R. Simpson.
His piece stands as the finest known example of this rare San Francisco strike.
Rarity is the main reason this coin commands such a massive price tag.
Researchers have confirmed only five genuine 1943 bronze cents from the San Francisco Mint.
The very first one came to light in 1944, found in pocket change by a fourteen-year-old named Kenneth Wing Jr. of Long Beach.
Collector desire for wartime off-metal errors has remained intense for generations.
Every major penny collector wants an authentic 1943 copper cent, but almost none will ever own one.
When one of the five known specimens reaches the auction block, top buyers compete aggressively.
Prices like this belong strictly to verified, certified museum-grade pieces.
Start by looking at the date and the mint mark on the front of the penny.
The date must clearly show 1943, and you should see an "S" directly below the numbers.
Grab a simple household magnet and test the coin first.
A regular 1943 steel cent sticks firmly to a magnet, but a genuine bronze cent will not stick at all.
Next, weigh the coin on an accurate gram scale.
A true bronze penny weighs about 3.11 grams, while a steel cent weighs only about 2.7 grams.
Look closely at the surface with a magnifying glass for tiny flecks of zinc left over from the steel production equipment.
If you want a quick check, you can scan the piece with CoinKnow to help verify basic details before seeking an expert.
Watch out for altered dates, because people often shave an 8 down to make it look like a 3 on a 1948 penny.
Many plated steel cents also exist because of old rumors that the Ford Motor Company offered a free car for one.
Due to the high number of fakes, sending any potential find to a major third-party grading service is essential.
For the quickest possible value check, see the free coin identifier apps picks that held up in testing.
Upload a photo and get an instant value, grade estimate, and error check — no jargon, no sign-up required.