Ovulation in a 28-day cycle: day 14
A 28-day cycle is the length behind most textbook figures: ovulation on day 14, the next period on day 29, and a due date 280 days after the last period.
Only a minority of people have exactly 28 days every month, so even here, tracking a few cycles shows your real pattern.
Ovulation is usually about 14 days before the next period, so in a 28-day cycle it falls on day 14 — exactly what most calculators assume. A 28-day cycle is within the usual adult range of about 21–35 days.
Your 28-day cycle, phase by phase
| Phase | Cycle days |
|---|---|
| Period (typical) | Days 1–5 |
| Follicular phase | Days 1–13 (13 days) |
| Fertile window | Days 9–15, best on days 12–14 |
| Ovulation | Day 14 |
| Luteal phase | Days 15–28 (14 days) |
Start LH ovulation tests around day 11; a positive result on day 12 or 13 points to ovulation on day 14.
If your cycle is sometimes 26 or 30 days
Few cycles are identical every month. If yours ranges between 26 and 30 days, ovulation could fall anywhere from day 12 to day 16, which widens your possible fertile days to days 7 to 17. Base the start of ovulation testing on your shortest recent cycle (day 9), and expect your period between day 27 and day 31.
| Cycle length | Ovulation | Fertile window |
|---|---|---|
| 26 days | Day 12 | Days 7–13 |
| 27 days | Day 13 | Days 8–14 |
| 28 days | Day 14 | Days 9–15 |
| 29 days | Day 15 | Days 10–16 |
| 30 days | Day 16 | Days 11–17 |
Example: a 28-day cycle starting today
| Period starts (day 1) | |
|---|---|
| Start ovulation tests (day 11) | |
| Fertile window (days 9–15) | – |
| Estimated ovulation (day 14) | |
| Next period / test day (day 29) |
Test for pregnancy from day 29 — see the Pregnancy Test Calculator for exact dates.