IRR Calculator

Evaluate investment performance from an initial cost and projected cash flows. Includes IRR, NPV check, and Show Work.

How to Use

  1. Enter the initial investment as a negative cash flow.
  2. Add future period cash flows in order by year, month, or chosen period.
  3. Optionally set a guess rate and max iterations.
  4. Click Calculate to solve IRR and review the NPV validation and Show Work.
Investment Snapshot
Track cash flow pattern, result quality, and quick validation signals.
Status: Waiting for input
IRR
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NPV @ IRR
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Payback
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Periods
0

Cash Flow Timeline

Negative bars are outflows. Positive bars are inflows.
Inputs & Settings
Enter one initial outflow and the future period cash flows used to solve IRR.
Usually entered as a negative number because it is money going out.
This controls labels only. IRR is solved per entered period.
Used by the solver as a starting point. Leave blank to use the default.
Higher values may help difficult cash flow patterns converge.

Cash Flow Rows

Enter each future inflow or outflow in order. You can add or remove rows as needed.

Period Cash Flow Notes Action
IRR requires at least one negative cash flow and one positive cash flow somewhere in the series.
Show Work (step-by-step)
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Work should show the NPV equation, entered cash flow series, selected guess, and iteration summary used to approximate the IRR.

IRR Formula

Quick answer: IRR is the discount rate that makes net present value equal to zero.

For a series of cash flows, the tool solves for the rate r where:

NPV = CF₀ + CF₁ / (1 + r)¹ + CF₂ / (1 + r)² + ... + CFn / (1 + r)ⁿ = 0
  • CF₀ is usually the initial investment and is often negative.
  • CF₁ ... CFn are future inflows or outflows.
  • r is the internal rate of return per entered period.
Some cash flow patterns can produce multiple IRRs or no valid IRR. The tool should flag those cases clearly.

FAQ

What does IRR tell me?

IRR estimates the rate of return that makes the present value of all entered cash flows balance to zero.

Why is the initial investment usually negative?

Because it represents money leaving you at the start of the project or investment.

Can IRR fail to solve?

Yes. Some cash flow patterns do not cross zero in a way that produces a valid IRR, and others can produce more than one possible IRR.

Is IRR annual by default?

IRR is per entered period. If your rows are yearly, the result is annual. If they are monthly, the result is monthly unless annualized.

Tool Info

Last updated:

Updates may include solver improvements, accessibility refinements, edge-case handling, and clearer investment reporting.