Project accounting is the practice of creating financial reports specifically designed to track the financial progress of projects, which can then be used by managers to aid project management.
Standard accounting is primarily aimed at monitoring financial progress of organizational elements (geographical or functional departments, divisions and the enterprise as a whole) over defined time periods (typically weeks, months, quarters and years).
Projects differ in that they frequently cross-organizational boundaries, may last for a anything from a few days or weeks to a number of years, during which time budgets may also be revised many times. They may also be one of a number of projects that make up a larger overall project or program.