Use this IRR calculator to find the discount rate that makes a project net present value equal zero. Enter the initial investment and future cash flows, including uneven cash-flow periods when relevant. The result gives internal rate of return for capital budgeting, private investments, and project comparisons, then can be compared with WACC or your required hurdle rate.
Related calculators and references
- Cluster hub: Investment & Valuation hub.
- Related calculator: DCF Calculator.
- Related calculator: NPV Calculator.
- Related calculator: WACC Calculator.
- Related calculator: Enterprise Value Calculator.
- Reference: [Internal rate of return definition](./).
- Reference: NPV Calculator.
How to Use the IRR Calculator
Follow these steps to calculate IRR and annualized IRR for a series of cash flows using CalcMastery. You’ll also see NPV at IRR for confirmation.
Select the cash flow frequency
Choose Yearly, Semiannual, Quarterly, or Monthly to match how your cash flows occur. This sets periods per year (1, 2, 4, or 12). If your data is monthly but you select Yearly, the annualized IRR will be wrong. Pick the frequency that matches your list of cash flows.
Enter the initial investment (outflow)
Type the upfront cost as a positive currency amount (e.g., 10000). The tool treats this as an outflow at time 0. Do not include currency symbols or commas as thousand separators (use 10000, not 10,000). Avoid adding a minus sign unless your project begins with an inflow instead of a cost.
List the cash flows by period
Enter your period-by-period amounts as a simple list (e.g., 2500, 3200, 4000, 4100). Use a dot “.” for decimals (75.5), and avoid thousand separators. Mark outflows with a leading minus sign when they occur after time 0. Do not repeat the initial outflow here—only list cash flows from period 1 onward.
Toggle decimals (optional)
Use “Show Decimals” if you want more precise percentage and currency outputs. Rounded displays can hide small differences; turn this on if you’re comparing similar projects. If values look odd, ensure you didn’t mix decimal comma with decimal point.
Review the results
Read IRR (per period) first—it’s the return for each selected period. Then see Annualized IRR, computed from the per-period rate using your chosen frequency. NPV at IRR should be approximately 0; if it isn’t, check for formatting issues or missing periods.
Frequently Asked Questions
These FAQs explain IRR, multiple cash-flow changes, reinvestment assumptions, and how IRR differs from NPV.
What is the internal rate of return (IRR)?
IRR is the discount rate that makes the net present value (NPV) of all cash flows equal to zero; it’s the rate implied by a project’s pattern of outflows and inflows and is often used to compare investments on a like-for-like basis.
Why can there be multiple IRRs?
If the cash-flow stream switches sign more than once (e.g., outflow → inflow → outflow), the NPV(r) polynomial can cross zero multiple times, yielding multiple valid discount rates. In such non-conventional cases, ranking projects by IRR can be misleading; NPV at an appropriate discount rate is preferred.
What happens if cash flows never change sign or no real IRR exists?
With all outflows (or all inflows), NPV(r) does not cross zero, so no real IRR exists. If NPV stays above or below zero for all feasible r, the tool reports that no IRR is found; decision-making should then rely on NPV at a chosen discount rate.
How are rounding and currency display handled?
Numeric computations use IEEE 754 round-to-nearest-ties-to-even. Percent outputs are rounded to two decimals for display. Monetary outputs use the currency’s ISO 4217 minor unit (e.g., 2 decimal places for USD) for display; internal calculations use higher precision and only round at presentation.
Sources & Methodology
- Data: Current
- Principles of Corporate Finance