The discounted cash flow is the total of cash flow in each period divided by 1 + the discount rate which is to the power of period number.

DCF = (CF/(1+r)^1)+.......(CF/(1+r)^n)

Where CF - Cash flow in the given period.

r - discount rate or the interest rate &

n - period number.

DCF is mainly used by the CFA or financial professionals for determining the final amount for any stock or Business. Hope this helps.