(11% is standard), minus the initial investment. If the net present value of cumulative cashflows is positive, then the project should be accepted, unless a more profitable investment is also availiable.
net present value
Money has a time value, net present value is future cashflows brought back to today’s value against a discount factor
To calculate the NPV of an investment, one must know the discount factor, cost of investment and expected incomes (based off accurate data)