Reviewed by Charles Potters
Fact checked by Vikki Velasquez
In capital budgeting, a number of approaches can be used to evaluate a project. Two very common methodologies are the internal rate of return (IRR) and net present value (NPV).
Each of these approaches produces a single number that management can use as an estimate of the contribution that a new investment or other initiative can make to the company in the future.
Each approach has distinct advantages and disadvantages.
Key Takeaways
- Both IRR and NPV are useful to decide what projects to green-light and what profitability a company can expect from them.
- Internal rate of return (IRR) estimates an expected percent return on the investment.
- Net present value (NPV) estimates the outcome in a positive or negative dollar amount.
- Though the net present value method is more flexible, it isn’t useful when trying to compare projects of different sizes or analyze a project’s return timeline.
What Is IRR?
The internal rate of return (IRR) estimates the profitability of potential investments using a percentage value rather than a dollar amount. It excludes external factors such as capital costs and inflation.
IRR is also referred to as the discounted flow rate of return or the economic rate of return.
The IRR method simplifies the potential of a project to a single return percentage that management can use to determine whether a project is economically viable.
Many companies establish an internal required rate of return to use as a benchmark and may decide to move forward with a project only if the IRR meets or exceeds this benchmark.
IRR Pros and Cons
The IRR is simple to use and does not require a hurdle or benchmark rate. However, it ignores the size of a project.
What Is NPV?
A company’s net present value (NPV) is expressed in a dollar amount. It is the difference between a company’s present value of cash inflows and its present value of cash outflows over a specific time period.
NPV is calculated by estimating a company’s future cash flows related to a project. Then, these cash flows are discounted to present value using a discount rate representing the project’s capital costs, risk, and desired rate of return.
The sum of all discounted cash flows represents the net present value, and the net present value is the difference between the project cost and the income it generates over time.
NPV Pros and Cons
NPV is easy to interpret: if the NPV is positive, the project is profitable. If the NPV is negative, it is not. However, NPV isn’t useful when trying to decide which projects to take on as size or timeline aren’t considered.
Problems With IRR
The primary benefit of IRR is its simplicity: It’s easy to calculate and easy to interpret the result. However, it has several drawbacks.
IRR only uses one discount rate, and the true discount rate can change substantially over time – especially if the investment is a long-term project. Without modification, IRR does not account for changing discount rates, so it’s just not adequate for longer-term projects with periods of varying risk or changes in return expectations.
Another type of project for which a basic IRR calculation is ineffective is a project with a mixture of multiple positive and negative cash flows.
For example, consider a project for which the marketing department must reinvent the brand every couple of years to stay current in a trendy market.
The project has cash flows of:
- Year 1 = -$50,000 (initial capital outlay)
- Year 2 = $115,000 return
- Year 3 = -$66,000 in new marketing costs to revise the look of the project.
A single IRR can’t be used in this case. Recall that IRR is the discount rate or the interest needed for the project to break even given the initial investment. If market conditions change over the years, this project can have multiple IRRs.
In other words, long projects with fluctuating cash flows and additional investments of capital may have multiple distinct IRR values, making it impossible to evaluate.
The IRR method is also problematic when the discount rate of a project is not known. If the IRR is above the discount rate, the project is feasible. If it is below, the project is not. If a discount rate is not known, there is no benchmark to compare the project return against.
In cases like this, the NPV method is superior as projects with a positive NPV are considered financially worthwhile.
Using NPV
The advantage to using the NPV method over IRR using the example above is that NPV can handle multiple discount rates or varying cash flow directions. Each year’s cash flow can be discounted separately from the others, so the NPV method is more flexible when evaluating individual periods.
The NPV method is inherently complex and requires assumptions at each stage such as the discount rate or the likelihood of receiving the cash payment.
The NPV can be used to determine whether an investment such as a project, merger, or acquisition will add value to a company. If an NPV is positive, the sum of discounted cash inflows is greater than the sum of discounted cash outflows. The company will receive more economic benefit than it puts out, so the project, assuming the return is material and no capacity constraints are met, is beneficial to the company.
A negative NPV indicates a company’s cash outflows over the life of a project exceed what it is expected to receive. When a project’s NPV is negative, the project is not profitable and should not go forward.
Like the IRR method, there are disadvantages to the NPV method. It may be difficult to determine the required rate of return or discount rate to use to discount cash flow. Also, NPV calculations are biased towards larger projects. One project may have a higher NPV, but its rate of return may be lower, and the total cash outlay may be higher than a smaller project.
Is IRR or NPV Better for Capital Budgeting?
The choice depends on the use.
IRR is useful when comparing multiple projects against each other. It also is more appropriate when it is difficult to determine a discount rate.
NPV is better in situations where there are varying directions of cash flow over time or multiple discount rates.
How Is IRR Calculated?
IRR is calculated by setting the NPV of a series of cash flows to zero and solving for the discount rate. IRR can be solved manually through trial and error, though it is more efficient to use software to do the calculations.
How Is NPV Calculated?
NPV is calculated by finding the present value of each cash flow for each period, including any initial cash outflow that occurs immediately. The discount rate used is self-selected as the required rate of return for the project. Once all discounted cash flows have been calculated, add all cash flows to arrive at the net present value.
The Bottom Line
Internal rate of return (IRR) and net present value (NPV) are two ways to arrive at a single number that indicates the potential return on a capital project that is being considered.
Each method has its uses and its drawbacks. IRR is easier to calculate. NPV is easier to interpret.