Financial

IRR Formula

Calculates the internal rate of return for a series of cash flows occurring at regular intervals. IRR is the discount rate that makes the net present value of all cash flows equal to zero. It's the standard metric for evaluating the profitability of projects and investments.

Syntax

IRR(values, [guess])
ParameterDescription
values Parameter of the IRR function.
[guess] (Optional.) Parameter of the IRR function.
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Examples

Business project evaluation

Formula
=IRR({-100000, 30000, 35000, 40000, 45000})
14.5%. A $100K investment returning $30K-$45K over 4 years yields a 14.5% annual return.

Rental property annual returns

Formula
=IRR({-200000, 18000, 18000, 18000, 18000, 250000})
12.8%. Buy for $200K, collect $18K/year in rent for 4 years, sell for $250K — that's a 12.8% annual return.

Project that destroys value

Formula
=IRR({-50000, 10000, 10000, 10000, 10000})
-5.4%. Total returns of $40K on a $50K investment over 4 years actually represents a negative return when time value is considered.

Common Errors

#NUM!

IRR cannot find a result after 20 iterations. Provide a guess argument, or the cash flows may not have a valid IRR (e.g., all positive or all negative values).

#VALUE!

The values range contains non-numeric entries.

Tips

Must have both signs

Cash flows need at least one negative and one positive value. Typically, the first value is negative (initial investment) and subsequent values are positive (returns).

IRR assumes reinvestment at the same rate

IRR implicitly assumes you reinvest all returns at the IRR rate itself, which may be unrealistic. For a more conservative estimate, consider MIRR (Modified IRR) if available.

Compare IRR to your cost of capital

If your IRR exceeds your cost of capital (e.g., 14% IRR vs 10% required return), the project creates value. If it's below, pass on it.

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