Talk:Discounted payback period

Example

• PB = 5 y (ROR=0)
• DPB = 7.3 y (ROR=10%)

ROR 10,0%

T y*	CF €	Total €		DCF €0y NPV €0y		IRR %
0	-100	-100		-100	-100		
1	20	-80		18,2	-81,8		-80
2	20	-60		16,5	-65,3		-45
3	20	-40		15,0	-50,3		-22
4	20	-20		13,7	-36,6		-8,4
5	20	0		12,4	-24,2		0
6	20	20		11,3	-12,9		5,5
7	20	40		10,3	-2,6		9,2
8	20	60		9,3	6,7		11,8
9	20	80		8,5	15,2		13,7
10	0	80		0,0	15,2		13,7
* or month, or any uniform time interval (then ROR is based on that time interval).

Key

CF  = Cash Flow, €
DCF = Discounted Cash Flow, €0y (= € @ ref.y=0)
ROR = Rate Of Return, € earned / € invested / y, % per year (or per time interval chosen)
NPV = Net Present Value, €0y
IRR = Internal Rate of Return (ROR to have NPV=0)
PB  = Pay Back period, y
DPB = Discounted Pay Back period, y
T   = project duration, y

INPUT    => OUTPUT
CF       => PB(ROR=0, time to get NPV=0)
CF,T     => IRR(ROR to get NPV=0)
CF,ROR   => DPB(time to get NPV=0)
CF,T,ROR => NPV