# IRR Calculator

> Calculate the internal rate of return from a series of cash flows. Free irr calculator with the formula shown - runs entirely in your browser, no signup.

- **Canonical URL:** https://boringtoolskit.com/irr-calculator/
- **Category:** Everyday Calculators
- **Evidence level:** authored-methodology
- **Reviewed:** August 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

IRR is the discount rate r where Σ cash_flow_t ÷ (1+r)^t = 0.

## Sources

- [Calculation methodology and verification standard](/methodology/)

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