IRR Calculator
Use this internal rate of return online calculator to estimate the return rate that makes the net present value (NPV) of your cash flow stream equal to zero.
Educational tool only. Results depend on cash flow timing assumptions and may not represent real-world investment outcomes.
What is the internal rate of return (IRR)?
The internal rate of return is the discount rate that sets the net present value of a project’s cash flows to zero. In practical terms, IRR is the project’s implied compound return per period, based on expected inflows and outflows.
Investors use IRR to compare opportunities of different sizes and durations. If a project’s IRR is higher than your required return (sometimes called hurdle rate), it may be financially attractive.
How to use this internal rate of return online calculator
Step-by-step
- Enter your initial investment as a positive number (for example, 10000).
- Enter projected future cash flows by period (for example, 3000, 3500, 4000, 4500).
- If your cash flows are monthly or quarterly, set periods per year accordingly.
- Click Calculate IRR to get the per-period IRR and annualized equivalent.
If you also enter a discount rate, the tool calculates NPV at that rate so you can compare a target return versus the computed IRR.
IRR formula and interpretation
IRR solves this equation:
0 = CF0 + CF1/(1+r)^1 + CF2/(1+r)^2 + ... + CFn/(1+r)^n
Where:
- CF0 is usually the initial outflow (negative cash flow).
- CF1...CFn are future inflows/outflows.
- r is the IRR per period.
Because this equation usually cannot be rearranged into a simple closed form, calculators use iterative numerical methods.
How this calculator computes IRR
Numerical methods
This page first uses the Newton-Raphson method for speed. If that does not converge, it falls back to a bracket-and-bisection approach for stability.
Validation checks
- Requires at least one negative and one positive cash flow.
- Detects sign changes in the sequence and warns when multiple IRRs may exist.
- Rejects invalid entries and non-numeric values.
Example scenario
Suppose you invest $10,000 today and expect $3,000, $3,500, $4,000, and $4,500 over the next four years. The calculator can estimate the annual IRR for this stream.
If your required return is 8% and the computed IRR is higher, the project may pass your financial screen. If it is lower, you may want to reconsider or renegotiate costs.
Common IRR pitfalls
- Multiple IRRs: Cash flows that change sign more than once can produce more than one mathematically valid IRR.
- Reinvestment assumption: IRR can imply reinvestment at the same rate, which may be unrealistic.
- Scale blindness: A high IRR on a tiny project may create less value than a moderate IRR on a large project.
- Timing sensitivity: Delayed inflows can significantly reduce IRR even when total cash received is unchanged.
IRR vs NPV: which one should you trust?
Use both. IRR gives an intuitive rate, while NPV gives dollar value created at a chosen discount rate. In conflicting rankings, NPV is often preferred for value maximization because it directly measures wealth impact.
Frequently asked questions
Is IRR the same as ROI?
No. ROI is usually a simple percentage gain over total cost. IRR accounts for timing and compounding across periods.
Can IRR be negative?
Yes. A negative IRR means projected cash flows do not recover value at a positive growth rate.
Can I use monthly cash flows?
Yes. Enter monthly cash flows, set periods per year to 12, and the calculator will provide an annualized equivalent return.