Setnakhte was originally believed to have enjoyed a reign of only two years based upon his Year 2 Elephantine stela but his third regnal year is now attested in Inscription No. 271 on Mount Sinai. If his theoretical accession date is assumed to be II Shemu 10, based on the date of his Elephantine stela, Setnakhte would have ruled Egypt for at least two years and 11 months before he died, or nearly three full years. This date is only three months removed from Twosret's highest known date of Year 8, III Peret 5, and is based upon a calculation of Ramesses III's known accession date of I Shemu 26. Peter Clayton also assigned Setnakhte a reign of three years in his 1994 book on the Egyptian pharaohs.