A real mint error is a coin that left the Mint wrong: struck off center, on a blank that was clipped or meant for another coin, from a doubled or cracked die, or through debris that got between the die and the metal. Those coins sell for approximately $5 to a few hundred dollars for common error types, and into five and six figures for famous ones such as the 1955 doubled die cent or the 1943 bronze cent. Most coins people think are errors are not. Machine doubling, coins squeezed in a vise, plated or discolored coins and coins with metal ground off the edge are damage done during or after striking, and they are worth face value. The test is whether the oddity could only have happened inside the coining press.
Quick answer
- Most "error coins" in jars are damage or machine doubling, worth face value.
- Look for raised metal from the die, missing metal with a matching rim effect, or a design struck off the blank.
- Real errors on silver, older or key-date coins, and dramatic errors with a full date, bring the most.
How to check yours, step by step
- Look at the rim all the way around. A genuine off-center strike has a blank, unstruck crescent with no rim on that side, and the design ends sharply. A clipped planchet has a smooth curved or straight notch in the edge. Grinding or cutting leaves scratches, sharp burrs and bright metal.
- On a clip, check the rim opposite the notch. A real clip shows the Blakesley effect: the rim directly across from the clip is weak or flat, because the blank never got a full raised rim in the upsetting mill. If the opposite rim is normal, the notch was probably made after striking.
- For doubling, examine the letters with a 10x loupe. A doubled die shows two complete, rounded impressions of the same letters, often with notches where the two outlines meet, and the doubling is consistent on every coin from that die. Machine doubling is a flat, shelf-like edge on one side of the letters, as if the letter were smeared.
- Decide whether a feature is raised or sunken. A die crack prints as a thin raised line, because metal flowed into a crack in the die. A scratch is sunken. A cud, where a piece of die broke away at the rim, prints as a raised, featureless blob joined to the rim. Gouges and dents are pushed in.
- Weigh it and measure it. A wrong planchet error weighs what the other coin's blank weighs: a cent struck on a dime blank weighs about 2.27 grams instead of 2.5 or 3.1, and its diameter is smaller than a normal cent with part of the design missing. A coin that weighs the right amount but looks too thin and wide was probably squeezed.
- Check the color against the metal. A copper-nickel coin that looks coppery on one side may be missing its clad layer, but acid and heat can do the same thing. Missing clad layers weigh less by a predictable amount and keep crisp design detail; acid leaves pitting and soft edges.
- Note the date and denomination. An off-center cent with a full date is worth several times one without. The same error on a quarter or half dollar is worth more than on a cent, and on silver or older coins more again.
Error types and typical premiums
Error values depend on how dramatic the error is, the denomination, the date and the condition. The ranges below are typical for uncirculated or lightly worn modern US coins.
| Error type | What it looks like | Cent | Quarter or larger |
|---|---|---|---|
| Off-center strike, 5-15% | Small blank crescent, full design | $3-10 | $10-30 |
| Off-center, 30-60%, date visible | Half the design missing, date readable | $15-50 | $50-200+ |
| Broadstrike | Wider, flatter coin with no reeding, design centered | $5-20 | $30-100 |
| Clipped planchet, curved | Smooth notch, weak opposite rim | $2-10 | $10-50 |
| Multiple or large clips | Two or more notches, or a big bite | $10-50 | $50-200+ |
| Double strike, second off center | Two overlapping images | $100-300 | $300-1,000+ |
| Wrong planchet (wrong denomination) | Undersized or oversized, wrong metal | $100-500 | $200-1,500+ |
| Missing clad layer | Copper color on one side, light weight | n/a | $50-300 |
| Doubled die (listed variety) | Two rounded outlines on lettering | $5 to thousands | $20 to thousands |
| Repunched mint mark | Second mint mark letter offset under the first | $2-50 | $10-150 |
| Die crack | Thin raised line across design | Under $5 | $1-20 |
| Die cud | Raised blob joined to the rim | $10-50 | $20-150+ |
| Struck through grease | Soft, missing design area | Under $5 | $1-10 |
| Struck through cloth, wire or a dropped filler | Texture or shape impressed into the coin | $10-75 | $20-200+ |
| Lamination flaw | Peeling flake of metal | $2-10 | $5-30 |
These approximate figures are for coins without wear, cleaning or later damage. Worn errors sell for less, and dramatic examples with a full date sell at the top of each range or above it.
Famous errors and what they bring
| Coin | What happened | Typical range |
|---|---|---|
| 1943 bronze cent | Leftover bronze blank struck in the steel year | $100,000 to over $1 million |
| 1944 steel cent | Leftover steel blank struck in the bronze year | $75,000 to six figures |
| 1955 doubled die cent | Badly doubled working die | $1,000-2,000 worn, more uncirculated |
| 1969-S doubled die cent | Doubled die, very few known | Five figures and up |
| 1937-D three-legged Buffalo nickel | Over-polished die removed a leg | $600-900 worn, thousands uncirculated |
| 2004-D Wisconsin extra leaf quarter | Die gouge creating an extra corn leaf | $50-200 |
| 2000-P Sacagawea and Washington mule | Quarter obverse paired with dollar reverse | Six figures |
| 1970-S proof quarter on a 1941 Canadian quarter | Foreign coin fed into a proof press | Five figures |
| 1972 doubled die cent | Doubled working die | $200-400 worn |
The wheat penny guide and the pennies checklist cover the cent varieties in more detail, and the Buffalo nickel guide covers the three-legged 1937-D.
Damage and doubling that people mistake for errors
Most coins sent in as errors fall into a few groups, and none of them carry a premium.
Machine doubling (strike doubling). The die bounces or twists slightly as it lifts off the coin and pushes a flat shelf into the edges of the design. It looks like a shadow on one side of the letters and is very common on modern coins. It is not a doubled die.
Squeezed and hammered coins. Coins pressed in a vise or between two other coins become thin and wide, or thick and narrow, with the design spread or blurred. They can look like a broadstrike, but a broadstrike keeps sharp, centered design detail and normal weight, while a squeezed coin has distorted lettering and often tool marks.
Plated, colored and heat-damaged coins. Silver, gold or copper colored coins that should not be that color have been plated, dipped or heated. Fire turns coins blue, purple, brown or rainbow colored. None of it happened at the Mint.
Edge grinding and cut clips. A notch cut with a saw or file has straight tool marks, a bright surface inside the cut and a normal rim opposite it. A genuine clip is smooth, slightly irregular and comes with the Blakesley effect.
Acid and corrosion. Chemical damage eats the surface unevenly, making a coin look thin, pitted or "missing a layer." A real missing clad layer has a clean, crisp surface and a specific lower weight.
Contact marks and gouges. Dents and scratches from circulation are sunken into the coin. Die cracks and die breaks are raised. That single test sorts out a large share of so-called errors.
Common mistakes
- Calling any doubling a doubled die. Machine doubling is far more common than true doubled dies, and only listed doubled die varieties carry real premiums.
- Treating a die crack as a big find. Die cracks are interesting but common. Most add a few dollars at most.
- Mistaking post-mint damage for a broadstrike or off-center strike. Check the weight and the sharpness of the design.
- Pricing from listings instead of sales. Asking prices for "rare error" coins on marketplaces are often many times what such coins actually sell for.
- Assuming discolored coins are off-metal errors. A gold-colored cent or a coppery dime is almost always plated or chemically altered.
- Forgetting that errors can be faked. Altered dates, plated 1943 cents, and fabricated mules and off-metal strikes all circulate in the market.
What to photograph
- Both sides straight on, with the whole coin and its rim in frame. Off-center strikes and clips are judged from the full outline.
- The edge, especially for clips, broadstrikes and wrong planchets, showing reeding or its absence.
- The rim opposite any clip, close up, to show or rule out the Blakesley effect.
- A 10x macro of doubled letters with light from the side, which separates rounded die doubling from flat machine doubling.
- The scale reading to 0.01 gram if possible, for wrong planchets, missing clad layers and squeezed coins.
- A ruler or caliper photo for size differences.
When to get it looked at in person
Minor errors under about $50 are rarely worth grading fees. For anything more dramatic, such as a double strike, a wrong planchet, a large off-center strike with a full date, a mule or a doubled die candidate, an expert look in person is worth it.
- Error coin dealers and local coin shops can usually tell damage from a mint error in seconds, often at no charge.
- PCGS and NGC both attribute and encapsulate mint errors, with the error type printed on the label. Fees start in the tens of dollars per coin and rise with value and speed, plus shipping and membership. Encapsulated errors sell more easily and for more.
- Variety attribution services confirm listed doubled dies and repunched mint marks for a modest fee, which matters because unlisted minor doubling sells for very little.
When selling a collection of errors, keep the coins in soft, non-PVC flips and do not clean or straighten anything. Error buyers judge the strike, the surface and the weight, and a coin that has been handled roughly loses value quickly. A dramatic error sells best through a specialist dealer or a coin auction, while small lots of minor clips and off-centers are often easier to sell as a group.