The average accounting return (AAR) is the average project earnings after taxes and depreciation, divided by the average book value of the investment during its life.Approach to making capital budgeting decisions involves the average accounting return (AAR). There are many different definitions of the AAR. However, in one form or another, the AAR is always defined as: Some measure of average accounting profit divided by some measure of average accounting value. The specific definition we will use is: Average net income divided by Average book value. It is kinds of decision rule to accept or reject the finance project. For decide to these projects value, it needs cutoff rate. This rate is kind of deadline whether this project produces net income or net loss.