The term “non-sufficient funds” (NSF), or “insufficient funds,” refers to the status of a checking account that does not have enough money to cover transactions.
The acronym NSF also describes the fee charged when a check is presented but cannot be covered by the balance in the account.
The average NSF fee in the U.S. ranges between $27 and $35.
NSF fees are slightly different from overdraft fees, which apply when a bank accepts checks that overdraw checking accounts.