IRR with a direct non-number gives #NUM!, and the guess is still checked

FN-IRR-001: IRR with a direct non-number gives #NUM!, and the guess is still checked

Quirk · measured · recorded 2026-11-04

Text or a logical typed directly as the values argument of IRR is not an error of type: "", "2", "x", "0", "-2", TRUE and FALSE all give #NUM!, never #VALUE!. The guess is read anyway, and its error wins: with any of those values, a guess of "x" gives #VALUE! and a guess of NA() gives #N/A, while 0.1 or an empty guess leaves #NUM!. A direct error in values wins over the guess: IRR(NA(),"x") is #N/A.

Basis: 40 recorded readings: seven direct non-numbers and NA() as values, each with five guesses (none, 0.1, "x", NA(), empty).

Open: A reference to one cell holding the same values answers differently. Those readings are not in a published capture, so this note covers direct values only.