The legal line is based primarily on the maximum possible punishment, not how serious the crime "sounds." It's a defined threshold, not a subjective judgment.
A misdemeanor is generally any crime punishable by up to one year in jail, served in a local or county jail rather than a state or federal prison. Misdemeanors are often split into classes (Class A, B, C, or similar, depending on the state) that set escalating maximum fines and jail time within that under-one-year range. Examples include things like petty theft, simple assault, first-offense DUI, or vandalism, though specifics vary significantly by state.
A felony is a crime punishable by more than one year, served in a state or federal prison rather than county jail. Felonies are also typically tiered by severity, going up to the most serious classifications that can carry life sentences or, in some jurisdictions, the death penalty. Examples include things like robbery, serious drug trafficking, and homicide.
The one-year line comes from federal law (18 U.S.C. ยง 3559) and most states follow a similar structure, though the exact threshold and classification details differ state to state, so the same act can sometimes be charged as a misdemeanor in one state and a felony in another.
Beyond time served, the classification carries consequences that extend well past the sentence itself. A felony conviction can result in loss of voting rights (temporarily or permanently depending on the state), loss of the right to own or possess firearms, difficulty obtaining professional licenses, immigration consequences for non-citizens, and a permanent mark on background checks that affects employment and housing. Misdemeanors carry lighter collateral consequences, though they still appear on background checks and aren't simply erased.
Prosecutors also have some discretion: a "wobbler" offense in some states can be charged as either a misdemeanor or a felony depending on circumstances, the defendant's criminal history, and plea negotiations. So while the underlying legal definition is fixed to sentence length and where it's served, how a specific act gets charged isn't always automatic.