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Payback & Profitability Index Calculator

Find simple payback years, NPV, and profitability index for a level annual cash inflow.

 

 

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Payback (years)
NPV
PI

About this calculator

Use this when a project costs a lump sum up front and then throws off roughly the same cash each year. Simple payback ignores the time value of money; NPV and PI do not. Discounted payback is not computed here.

Payback years = investment ÷ annual cash. NPV = PV of the annuity − investment, where PV = annual × (1 − (1 + r)^(−n)) / r (or annual × n if the rate is essentially zero). PI = PV of inflows ÷ investment. Type 8 for an 8% discount rate. All money figures share one currency.

Investment: Up-front outlay (positive number).

Annual cash: Level inflow each year after the investment.

Discount rate (%): Yearly hurdle rate as a percent.

Years: How many years the annual cash lasts (used for NPV and PI, not for simple payback).

Payback (years): Undiscounted years to recover the investment.

NPV: Net present value of the level inflows minus the investment.

PI: Profitability index (PV of inflows over investment).