IRR Calculator
The internal rate of return is the discount rate at which NPV is zero: investing 1000 for 300 a year over 5 years has an IRR of 15.2382 %.
Separate with commas or spaces; use a minus sign for outflows.
15.2382371166615 %
Full answer, then cut to fewer decimals (not rounded):
- 15.2382371166615 %
- 15.238237116661 %
- 15.23823711666 %
- 15.2382371166 %
- 15.238237116 %
- 15.23823711 %
- 15.2382371 %
- 15.238237 %
- 15.23823 %
- 15.2382 %
- 15.238 %
- 15.23 %
- 15.2 %
- NPV at the IRR
- −0.00
- Payback period
- 3.333 periods
| Rate | NPV |
|---|---|
| 0 % | 500.00 |
| 5 % | 298.84 |
| 10 % | 137.24 |
| 15 % | 5.65 |
| 20 % | −102.82 |
| 25 % | −193.22 |
| 30 % | −269.33 |
Step-by-step solution
- IRR is the rate r where NPV = Σ CFₜ ÷ (1 + r)ᵗ − C₀ = 0
- Solved numerically: r = 15.2382 %
- Check: NPV at 15.2382 % = −0.00
IRR Formula
0 = Σ CFₜ ÷ (1 + IRR)ᵗ − C₀
CFₜ cash flow in period t, C₀ initial investment; solved numerically
Worked Example
An investment of 1000 returning 300 a year for 5 years:
- IRR is the rate r where NPV = Σ CFₜ ÷ (1 + r)ᵗ − C₀ = 0
- Solved numerically: r = 15.2382 %
- Check: NPV at 15.2382 % = −0.00
Payback period: 3.333 periods
| Rate | NPV |
|---|---|
| 0 % | 500.00 |
| 5 % | 298.84 |
| 10 % | 137.24 |
| 15 % | 5.65 |
| 20 % | −102.82 |
| 25 % | −193.22 |
| 30 % | −269.33 |
Frequently asked questions
How do I calculate IRR in Excel?
Put the initial outflow as a negative number followed by the inflows, then use =IRR(A1:A6). For −1000 and five inflows of 300 it returns 15.24 %.
Why is there no formula for IRR?
The NPV equation is a polynomial in 1/(1 + r), which has no general closed-form solution beyond simple cases. IRR is found by trial and error or a numerical method, as this calculator does.
When can IRR be misleading?
With cash flows that change sign more than once there can be several IRRs, and IRR can rank mutually exclusive projects differently from NPV. Use NPV for the final decision.
Sources
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). IRR Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/irr-calculator/
IEEE
Scientific Converters, "IRR Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/irr-calculator/