# Discounted Payback Period Method

Definition

The discounted payback period method is based on the discounted cash flows technique and is used in project valuation as a supplemental screening criterion. In simple words, it is the number of years needed to recover initial cost (cash outflows) of a project from its future cash inflows. To calculate it, we need consequentially add the discounted value of each future cash inflow as long as the initial cost will be recovered.

Formula

The discounted payback period can be calculated as follows:

where p is a number of a period with the last negative value of cumulative discounted cash flow, |CDCFp| is an absolute value of the last cumulative discounted cash flow, and CDCFp+1 is the first positive value of cumulative discounted cash flow.

Decision rule

It’s not recommended to use the discounted payback period as a single screening criterion unlike the net present value (NPV) or internal rate of return (IRR). In case of a mutually exclusive project, however, it can be used as a supplemental criterion. Other things being equal, the project with a shorter payback period should be accepted.

Example

Two mutually exclusive projects are shown in the table below.

Both of them have a positive NPV of \$3,564K for Project Y and \$3,934K for Project Z and a cost of capital of 12%. In terms of NPV as a single screening criterion, Project Z contributes more to shareholder value than Project Y and therefore should be accepted. In terms of liquidity and uncertainly risk, however, the acceptance of Project Z is not as obvious as it might seem at first glance. Let’s use the discounted payback period method as a supplemental criterion.

As a first step, we need to calculate all values of discounted cash flows for both projects,

e.g., discounted cash flows of Project Y are as follows:

DCF0 = -20,000/(1+0.12)0= \$-20,000K

DCF1 = 9,000/(1+0.12)1= \$8,036K

DCF2 = 8,000/(1+0.12)2= \$6,378K

DCF3 = 6,000/(1+0.12)3= \$4,271K

DCF4 = 5,000/(1+0.12)4= 3,178

DCF5 = 3,000/(1+0.12)5= 1,702K

As a second step, we need to calculate all values of cumulative discounted cash flows for both projects,

e.g., cumulative discounted cash flows of Project Y are as follows:

CDCF1 = -20,000+8,036 = \$-11,964K

CDCF2 = -11,964+6,378 = \$-5,587K

CDCF3 = -5,587+4,271 = \$-1,316K

CDCF4 = -1,316+3,178= \$1,862K

CDCF5 = 1,862+1,702 = \$3,564K

The last negative value of cumulative discounted cash flow for Project Y was during the third year and during the fourth year for Project Z. Thus, the discounted payback period of Project Y is 3.41 years and 4.31 years for Project Z.

In terms of the discounted payback period, Project Y looks more attractive because it has greater liquidity and lower uncertainty risk.

Calculator

To calculate the discounted payback period, you can also use our online calculator.