What are error coins and how are they made?
Common Types of Mint Errors
Mint errors happen when a coin is struck incorrectly or with the wrong materials. Popular types include off-center strikes (the design is shifted), broadstrikes (struck without a collar, so the metal spreads), and wrong planchet errors (a coin struck on a blank meant for a different denomination).
Other errors involve the die itself, like doubled dies (the design is impressed twice) or repunched mintmarks. Some errors occur after striking, such as clipped planchets or lamination errors. Each type has its own collecting niche and value range.
- Off-center: design shifted from center.
- Broadstrike: struck without collar, wider and thinner.
- Wrong planchet: struck on a blank for another coin.
- Doubled die: design doubled from die misalignment.
- Clipped planchet: a piece of metal missing from the blank.
How Errors Are Created
Most errors occur when the minting machinery malfunctions or when a blank isn't properly seated in the press. For example, an off-center strike happens when a planchet isn't centered in the collar before the die hits it. A wrong planchet error occurs when a blank for one denomination accidentally enters the press for another.
Die errors like doubled dies result from the die being hubbed multiple times with slight misalignment. These errors are often caught by quality control, but some slip into circulation. The mint has become more automated, so many classic errors are less common today, but new ones still appear.
- Planchet not seated correctly → off-center or broadstrike.
- Wrong blank fed into press → wrong planchet error.
- Die hubbed twice → doubled die.
- Collar malfunction → broadstrike or partial collar.
Common mistakes
- Thinking all error coins are valuable—many common errors are worth only a few dollars.
- Confusing damage (like post-mint scratches or dents) with a true mint error.
- Assuming any odd-looking coin is an error; some are just worn or altered.
