Complete guide
IRR Calculator: formula, worked example and interpretation
Solve the periodic internal rate of return that sets a series of cash flows to net present value zero. Enter the known values and the result updates instantly with an auditable breakdown.
What the IRR Calculator answers
Solve the periodic internal rate of return that sets a series of cash flows to net present value zero.
Use the breakdown to compare the result with the source values before making a decision.
Formula and variables
The calculation uses 0=Σ CFₜ/(1+IRR)^t. Every variable comes directly from a labeled field.
0=Σ CFₜ/(1+IRR)^tWorked example
An initial −$10,000 followed by four positive cash flows is solved for the discount rate where NPV equals zero.
Changing any field recalculates the result immediately, so nearby scenarios can be compared without reloading the page.
How to use the result
Treat the result as a planning value and compare it with the detailed rows shown beside it.
Keep units and time periods consistent. Use the share or PDF action to preserve the exact assumptions.
Assumptions and scope
Cash-flow patterns with more than one sign change can have multiple IRRs or none; compare NPV at an appropriate hurdle rate.
The calculator exposes its assumptions instead of filling missing facts with hidden estimates.
Accuracy checks
Confirm the units, dates, rates and source figures before relying on the output.
Round only the displayed answer; Calculator24 keeps full JavaScript precision for intermediate arithmetic and exported values.
Input and output checklist
| Item | What to enter or review |
|---|---|
| Inputs | Cash flows from period 0, Initial guess (%) |
| Equation | 0=Σ CFₜ/(1+IRR)^t |
| Example | An initial −$10,000 followed by four positive cash flows is solved for the discount rate where NPV equals zero. |
| Limit | Cash-flow patterns with more than one sign change can have multiple IRRs or none; compare NPV at an appropriate hurdle rate. |
Frequently asked questions
What does this IRR Calculator calculate?
Solve the periodic internal rate of return that sets a series of cash flows to net present value zero.
Which formula does it use?
0=Σ CFₜ/(1+IRR)^t
Does the result update while I type?
Yes. Valid changes recalculate after a short delay and the previous result is not substituted for invalid input.
Which assumptions should I check?
Check units, rates, dates and every source value shown in the form.
Is the result exact?
Cash-flow patterns with more than one sign change can have multiple IRRs or none; compare NPV at an appropriate hurdle rate.
Can I save or share the calculation?
Yes. Copy, Share, WhatsApp, PDF/Print, CSV, comparison and parameterized-link actions are available.
What to keep in mind
Cash-flow patterns with more than one sign change can have multiple IRRs or none; compare NPV at an appropriate hurdle rate.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.