Bookkeeping (also book-keeping or book keeping) is the recording of all financial transactions undertaken by an individual or organization. The organization may be a business, a charitable organization or even a local sports club. Bookkeeping is "keeping records of what is bought, sold, owed, and owned; what money comes in, what goes out, and what is left." A financial transaction is any event that involves money.

Individual and family bookkeeping involves keeping track of income and expenses in a cash account record, checking account register, or savings account passbook. Individuals who borrow or lend money also track how much they owe to others or are owed from others.

Bookkeeping may be performed using paper and a pen or pencil. With increasing complexity in tax regulations and to minimize calculation errors, many organizations use accounting software to assist in bookkeeping.