Are you talking about a Texas penny? Put into a leather belt and struck with a rubber mallet to make it larger. Take a photo next to a regular sized penny to show scale. Or, are you talking about the size of the D? In either case, it's one cent.
First ask if it's a Mint Error, this is more important than value!... then ask about worth I say not a Mint error
Can we help? YES Is this coin an error? NO What's the value? ONE CENT What should I do with it? SPEND IT
A normal cent is 19mm, so it was altered after it left the mint and is not an error. @Michael K has a good explanation.