Internal Rate of Return (IRR) is the discount rate at which an investment’s Net Present Value (NPV) equals zero. For a conventional project, an IRR above the required return generally supports acceptance. Comparing IRR with NPV helps ACCA and CFA students evaluate investment decisions and understand why a higher percentage return does not always mean greater value creation.
Imagine you invest ₹1,00,000 in a business project. The project is expected to generate ₹40,000 at the end of each of the next three years.
Contents
- What exactly is IRR?
- Let's calculate the IRR
- What does an IRR of 9.7% actually tell us?
- The IRR decision rule
- NPV vs IRR: Which one should you use?
- Can a project with a higher IRR be a worse investment?
- Are there situations where IRR does not work well?
- Why is IRR important in professional finance?
- Bringing NPV and IRR together
- The takeaway
You know the total cash you expect to receive is ₹1,20,000. You also know from our previous blog that the present value of those future cash flows, discounted at 10%, is approximately ₹99,475.
This gives the project a slightly negative Net Present Value (NPV).
But let's look at the same investment from a different angle.
Instead of asking how much value the project creates, what if you want to know the annual rate of return it offers?
That is where Internal Rate of Return (IRR) comes in.
What exactly is IRR?
In Part 2, we calculated NPV by choosing a required rate of return and discounting the future cash flows.
With IRR, we approach the problem differently.
We find the discount rate at which the NPV of the investment becomes zero.
In simple terms, IRR is the discount rate at which the present value of future cash inflows equals the initial investment.
Think of it this way:
With NPV, you choose the discount rate and calculate the value created.
With IRR, you find the discount rate that makes NPV equal to zero.
Both methods use the same expected cash flows. They simply answer different questions.
Let's calculate the IRR
Consider our project again.
| Year | Cash flow |
|---|---|
| Today | −₹1,00,000 |
| Year 1 | ₹40,000 |
| Year 2 | ₹40,000 |
| Year 3 | ₹40,000 |
We need to find the rate at which the present value of the three future cash inflows equals ₹1,00,000.
We know that at a 10% discount rate, the present value of the cash inflows is approximately ₹99,475. This is less than the initial investment, so the NPV is negative.
If we use a lower discount rate, the present value of the future cash flows increases.
At approximately 9.7%, the present value of the future cash inflows is equal to the initial investment of ₹1,00,000.
Therefore, the project's IRR is approximately 9.7% per year.
You do not normally need to find this rate through trial and error manually. Financial calculators and spreadsheet functions such as Excel's IRR can calculate it using the cash-flow series.
The important part is understanding what the answer means.
What does an IRR of 9.7% actually tell us?
It tells us that the project's expected cash-flow pattern corresponds to an internal rate of return of approximately 9.7% per year.
Now suppose you require a return of 10%.
The project offers an IRR of 9.7%, which is below your target. Based on the financial estimates, you would generally reject it.
But what if your required return were 8%?
The project's IRR would be higher than your required return. It would generally be acceptable under the IRR decision rule.
Notice that the project has not changed. Your required return has changed.
This is how IRR helps us evaluate whether an investment meets our return expectations.
The IRR decision rule
For a conventional investment, where you make an initial investment and subsequently receive cash inflows, the basic rule is:
| Comparison | Decision |
|---|---|
| IRR exceeds the required return | Generally accept |
| IRR is below the required return | Generally reject |
| IRR equals the required return | NPV is zero |
The required return is sometimes called the hurdle rate. It is the minimum return the business expects from the investment, taking its opportunity cost and risk into account.
NPV vs IRR: Which one should you use?
Now that we understand both concepts, let's compare them.
| Basis | NPV | IRR |
|---|---|---|
| What does it measure? | Value created in today's money | Rate of return implied by the cash flows |
| Result | Amount in rupees | Percentage |
| What do we compare it with? | Zero | Required rate of return |
| Main advantage | Shows how much value an investment creates | Makes the implied return easy to interpret |
| Main limitation | Requires an appropriate discount rate | Can give misleading comparisons between projects |
NPV and IRR are complementary tools. Neither should be interpreted without considering the expected cash flows, the risk of the investment and the assumptions behind the calculation.
Can a project with a higher IRR be a worse investment?
Yes. This is an important point to understand.
Imagine a company has two investment opportunities.
| Particulars | Project A | Project B |
|---|---|---|
| Initial investment | ₹1,00,000 | ₹10,00,000 |
| NPV | ₹20,000 | ₹1,00,000 |
| IRR | 20% | 15% |
Project A has the higher IRR: 20% compared with 15%.
If we look only at percentages, Project A appears more attractive.
However, Project B creates ₹1,00,000 of value, while Project A creates only ₹20,000.
If the company must choose only one of these mutually exclusive projects and its objective is to maximise value, NPV generally provides the better decision rule, assuming the estimates are reliable and the projects are comparable in risk.
The lesson is that a higher percentage return does not necessarily mean greater value creation.
IRR is useful for understanding returns, but it should not automatically determine which project a business chooses.
Are there situations where IRR does not work well?
Yes.
IRR is particularly straightforward when an investment involves an initial cash outflow followed by cash inflows. However, problems can arise when cash flows change direction more than once.
For example, a project may require a major additional expenditure several years after it begins generating revenue. Such cash-flow patterns can produce multiple IRRs or no meaningful real IRR.
IRR can also be misleading when comparing projects with different sizes, durations or cash-flow timing.
In these situations, NPV is often the more reliable basis for comparing investments, although the underlying assumptions and constraints still matter.
Why is IRR important in professional finance?
IRR is widely used in investment appraisal and financial analysis. Businesses use it to assess capital projects, while investors and analysts may use it to evaluate investment opportunities and cash-flow-based returns.
It is also an important concept in professional finance and accounting qualifications, including ACCA and CFA, where students learn how to calculate, interpret and compare investment returns.
Understanding the reasoning behind IRR makes it easier to handle more complex investment appraisal questions rather than simply applying a formula.
Bringing NPV and IRR together
Let's return to our original project.
You invest ₹1,00,000 and expect to receive ₹40,000 annually for three years.
At a required return of 10%:
The NPV is approximately −₹525.
The IRR is approximately 9.7%.
These two results tell the same underlying story.
The project offers a return slightly below the 10% required rate. Consequently, its NPV is slightly negative.
If the IRR were above the required return, the NPV would generally be positive for this type of conventional cash-flow pattern. If the IRR equalled the required return, the NPV would be zero.
This is the connection between the two concepts.
The takeaway
NPV and IRR help answer two different but closely related questions.
NPV asks: How much value does this investment create today?
IRR asks: What rate of return do the expected cash flows imply?
Both are useful when evaluating investments. NPV helps quantify value creation, while IRR expresses the investment's implied return as a percentage.
The concepts covered across these three blogs (the Time Value of Money, Present Value, Discount Factors, NPV and IRR) form the foundation of Financial Management (FM) and investment appraisal.
These are not just formulas to learn for an examination. They are fundamental concepts used in real-world financial decision-making and are important across professional courses such as ACCA, CFA and other finance and accounting qualifications.
Whether you are learning Financial Management for the first time or progressing towards a professional qualification, understanding these concepts will help you approach more advanced topics with greater clarity and confidence.
The objective is not just to learn the formulas. It is to understand the financial thinking behind them.
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