Net Present Value (NPV)
Net Present Value, or NPV, tells you whether a project is worth doing by measuring how much value it adds, expressed in today's money. Every project has money flowing out (the costs you pay, called outflows) and money flowing in (the benefits or revenue you receive, called inflows), often spread across several years. NPV brings all of those future amounts back to today's dollars and compares them.
To calculate it, you first find the Present Value of all the money coming in and the Present Value of all the money going out — that means discounting each future amount back to today using a chosen rate. Then you subtract the present value of the outflows from the present value of the inflows. Whatever is left over is the net value the project creates in today's terms.
Reading the result is the key skill: a positive NPV means the project is expected to earn more than it costs (after accounting for the time value of money), so it's generally worth pursuing. A negative NPV means it's expected to lose value and should usually be avoided. When comparing several projects, the one with the higher NPV is the better financial choice.
Project managers and selection committees use NPV constantly when deciding which projects to approve or fund. It's one of the most trusted tools because it accounts for both the size and the timing of every dollar, giving a single, comparable number.
Think of it like weighing a shopping deal: you line up everything you'll pay and everything you'll get, but you shrink each future amount down to what it's really worth today before putting them on the scale. If the "get" side outweighs the "pay" side, it's a good buy.
Imagine a project that costs $10,000 today (an outflow) and is expected to return $6,000 at the end of year 1 and $6,000 at the end of year 2, using a discount rate of 8%. First, discount the inflows to today: Year 1 = 6,000 / 1.08 = $5,556; Year 2 = 6,000 / (1.08)² = $5,144. Adding these gives PV of inflows = $10,700. The outflow of $10,000 is already in today's dollars. NPV = 10,700 − 10,000 = +$700. Because the result is positive, the project is expected to add about $700 of value in today's money, so it's worth doing.
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