Both of these measurements are primarily used in capital budgeting, the process by which companies determine whether a new investment or expansion opportunity is worthwhile. Given an investment opportunity, a firm needs to decide whether undertaking the investment will generate net economic profits or losses for the company.
To do this, the firm estimates the future cash flows of the project and discounts them into present value amounts using a discount rate that represents the project's cost of capital and its risk. Next, all of the investment's future positive cash flows are reduced into one present value number. Subtracting this number from the initial cash outlay required for the investment provides the net present value (NPV) of the investment.
Let's illustrate with an example: suppose JKL Media Company wants to buy a small publishing company. JKL determines that the future cash flows generated by the publisher, when discounted at a 12% annual rate, yields a present value of $23.5 million. If the publishing company's owner is willing to sell for $20 million, then the NPV of the project would be $3.5 million ($23.5  $20 = $3.5). The $3.5 million dollar NPV represents the intrinsic value that will be added to JKL Media if it undertakes this acquisition.
So, JKL Media's project has a positive NPV, but from a business perspective, the firm should also know what rate of return will be generated by this investment. To do this, the firm would simply recalculate the NPV equation, this time setting the NPV factor to zero, and solve for the now unknown discount rate. The rate that is produced by the solution is the project's internal rate of return (IRR).
For this example, the project's IRR could, depending on the timing and proportions of cash flow distributions, be equal to 17.15%. Thus, JKL Media, given its projected cash flows, has a project with a 17.15% return. If there were a project that JKL could undertake with a higher IRR, it would probably pursue the higheryielding project instead. Thus, you can see that the usefulness of the IRR measurement lies in its ability to represent any investment opportunity's return and to compare it with other possible investments.
To learn more, read Taking Stock Of Discounted Cash Flow, Anything But Ordinary: Calculating The Present And Future Value Of Annuities and Investors Need A Good WACC.

Which is a better measure for capital budgeting, IRR or NPV?
In capital budgeting, there are a number of different approaches that can be used to evaluate any given project, and each ... Read Answer >> 
How do you use internal rate of return to calculate a capital budget?
Learn about how the internal rate of return is used in the creation of a capital budget along with net present value and ... Read Answer >> 
How much debt is too much when calculating capital budgeting?
Learn how companies determine how much debt is acceptable when funding a new project by using the net present value to estimate ... Read Answer >> 
How do you use discounted cash flow to calculate a capital budget?
Learn how discounted cash flows are used in creating capital budgets as a part of the net present value and internal rate ... Read Answer >> 
How do you use net present value to calculate a capital budget?
Learn about the net present value calculation (NPV) and how the NPV rule is used in capital budgeting to compare the expected ... Read Answer >> 
What is the formula for calculating internal rate of return (IRR) in Excel?
Understand how to calculate the internal rate of return (IRR) using Excel and how this metric is used to determine anticipated ... Read Answer >>

Investing
Capital Budgeting: Which is Better, IRR or NPV?
Using internal rate of return and net present value for capital budgeting evaluations often end in the same result. But there are times when using NPV to discount cash flows makes more sense. 
Investing
An Introduction To Capital Budgeting
We look at three widely used valuation methods and figure out how companies justify spending. 
Entrepreneurship & Small Business
Calculating the Internal Rate of Return Using Excel
The internal rate of return on investments is explained and illustrated in different investment scenarios. 
ETFs & Mutual Funds
JKL: iShares Morningstar SmallCap Value ETF
Find out about the Shares Morningstar SmallCap Value ETF, and learn detailed information about this exchangetraded fund that focuses on smallcap equities. 
Investing
Return on Investment (ROI) Vs. Internal Rate of Return (IRR)
Read about the similarities and differences between an investment's internal rate of return (IRR) and its return on investment (ROI). 
Investing
Internal Rate Of Return: An Inside Look
Use this method to choose which project or investment is right for you. 
Markets
Internal Rate of Return Formula for Excel
The internal rate of return, or IRR, is a popular metric businesses use to measure a projectâ€™s return on investment. 
Financial Advisor
What's a Hurdle Rate?
Hurdle rate has two meanings. In the business world, a business typically makes a decision on a capital project based on the net present value approach. To determine the net present value, the ... 
Investing
Calculating Net Present Value at Different Points Using Excel
Calculating the net present value (NPV) of your investment projects using Excel. 
Trading
Understanding Internal Rate Of Return
Internal rate of return, or IRR, is one of the most popular methods of evaluating potential projects. Learn more about this important metric.

Net Present Value  NPV
Net Present Value (NPV) is the difference between the present ... 
Internal Rate Of Return  IRR
A metric used in capital budgeting measuring the profitability ... 
IRR Rule
A measure for evaluating whether to proceed with a project or ... 
Initial Cash Flow
The amount of money paid out or received at the start of a project ... 
IRR
The currency abbreviation or currency symbol for the Iranian ... 
The Net Internal Rate Of Return  Net IRR
A measure of a portfolio or fund's performance that is equal ...