A measure used to help decide whether or not to proceed with an investment. Net means that both the costs and benefits of the investment are included. To calculate net present value (NPV), first add together all the expected benefits from the investment, now and in the future. Then add together all the expected costs. Then work out what these future benefits and costs are worth now by adjusting future cashflow using an appropriate discount rate. Then subtract the costs from the benefits. If the NPV is negative, then the investment cannot be justified by the expected returns. If the NPV is positive, it can, although it pays to make comparisons with the NPVs of alternative investment opportunities before going ahead.