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IRR calculator

Find the discount rate that makes net present value zero for an initial investment followed by nonnegative returns.

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Answer

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IRR solves Σ cash flow at period t ÷ (1 + IRR)^t = 0. A bounded bisection solves the unique conventional-cash-flow root.

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Precision and calculation record
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Formula and assumptions
Supports conventional cash flows only, which have a unique root. Multiple sign changes are rejected rather than returning one arbitrary IRR. Periods must be equal; the result is per period, not automatically annual. Fixed assumptions only: no taxes, fees, changing returns, guarantees or product eligibility. Amounts share one currency.
In a list, use spaces, new lines, semicolons, or commas followed by a space. A comma between groups of three digits is a thousands separator.
Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.
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Using IRR calculator
IRR solves Σ cash flow at period t ÷ (1 + IRR)^t = 0. A bounded bisection solves the unique conventional-cash-flow root.
Supports conventional cash flows only, which have a unique root. Multiple sign changes are rejected rather than returning one arbitrary IRR. Periods must be equal; the result is per period, not automatically annual. Fixed assumptions only: no taxes, fees, changing returns, guarantees or product eligibility. Amounts share one currency.
Next: Net present value calculator
A worked example
Example inputs: cash flows, starting with investment = -100, 110. Internal rate of return per period (%) = 10.
Before you use the result
Supports conventional cash flows only, which have a unique root. Multiple sign changes are rejected rather than returning one arbitrary IRR. Periods must be equal; the result is per period, not automatically annual. Fixed assumptions only: no taxes, fees, changing returns, guarantees or product eligibility. Amounts share one currency.
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ToolOctopus. “IRR calculator.” Updated 2026-09-26. https://tooloctopus.com/irr-calculator.
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