No, actually they say day 14 is typically only if you have a consistent 28 day cycle..and even that is just the textbook estimation. In general, 14 days before your next period is supposed to be more accurate [meaning that your period will come on average 14 days after your ovulate]. But even that is just an just average estimation. Some women have long luteal phases and some have shorter ones. So even if two women have the same length cycle, they might not both ovulate on the same 14 days before the next period, as one might have luteal phase of 14 days and the other of 11 days. All women are different and have different ovulation patterns. So its better to familiarize ourselves with our own bodies and own cycles, rather than going on these generalized day counts