How it works
Find the rate r where Σ cash flow[t]/(1+r)^t = 0, by 180 bisection steps between −99.99% and 1,000,000%.
Input definitions
- Cash flows, starting with negative investment
- Plain text; maximum 200,000 characters.
A worked example
- Cash flows, starting with negative investment
- -1000, 600, 600
Assumptions & limits
Equal periods; one initial outflow followed by nonnegative inflows. No dates, tax or uncertain cash-flow forecasts. Conventional flows have at most one IRR.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.
Common questions
Is IRR annual or monthly?
IRR is per cash-flow period. Annual flows produce an annual IRR; monthly flows produce a monthly IRR. To annualize a monthly result r, use (1+r/100)^12−1, then multiply by 100.
Can IRR be negative or have multiple answers?
A negative IRR is possible when total inflows are below the investment. This tool restricts inputs to one initial negative outflow followed by nonnegative inflows, avoiding multiple sign changes. Use NPV for other cash-flow patterns.
Are these investment and borrowing results guaranteed?
No. These are deterministic estimates from the inputs and stated method, not predicted returns or lending offers. Actual fees, tax, timing and contractual terms may differ.
How does the Internal rate of return (IRR) tool work?
Find the rate r where Σ cash flow[t]/(1+r)^t = 0, by 180 bisection steps between −99.99% and 1,000,000%.
What are the assumptions and limits of Internal rate of return (IRR)?
Equal periods; one initial outflow followed by nonnegative inflows. No dates, tax or uncertain cash-flow forecasts. Conventional flows have at most one IRR.