Re: [R] calculating IRR (accounting) in R

From: McGehee, Robert <>
Date: Thu 01 Dec 2005 - 08:44:36 EST

If we define IRR implicitly such that NPV(C, IRR) = 0, then we can just write an IRR function that finds the zeros of the NPV function. Here are two such functions:

NPV <- function(C, r) {

    sum(C / (1 + r) ^ (seq(along = C) - 1))

IRR <- function(C) {

    uniroot(NPV, c(0, 1), C = C)$root

Hope this helps,

-----Original Message-----
From: paul sorenson [] Sent: Wednesday, November 30, 2005 3:50 PM To: r-help
Subject: [R] calculating IRR (accounting) in R

I am trying to replace a spreadsheet model of a project justification with an R script.

I can't seem to track down R functions to calculate Internal Rate of Return and NPV? Am I missing something? NPV doesn't seem so difficult to calculate (at least for a regular series) but I am struggling to identify how to solve for IRR in R.

It would be sufficient if it worked for a regular series but really useful if there was something that worked with irregular time series.

cheers mailing list PLEASE do read the posting guide! mailing list PLEASE do read the posting guide! Received on Thu Dec 01 08:51:18 2005

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