Capital budgeting decisions should be based on cash flows that are adjusted for the time value of money. The time value of money recognizes that a dollar received or spent in the future is less valuable than a dollar received or spent in the present. Calculations such as the internal rate of return, net present value, and excess present value include adjustments for the time value of money. In these calculations present value factors, financial calculators, or computer software are used to discount the cash flows to their present values.
Under accrual accounting, revenues and expenses are reported based on accounting principles. This means that revenues are reported when they are earned, and expenses are matched to the periods of the revenue. In other words, revenues and expenses are not reported on the income statement when the money is received or spent. Further, the revenue and expense amounts are not adjusted for the time value of money because of the monetary unit assumption.