Ovulation in a 29-day cycle: day 15
In a 29-day cycle ovulation falls around day 15, one day after the textbook day 14.
If your cycle swings between about 27 and 31 days, your fertile window can move by up to four days, so ovulation tests or cervical mucus checks help pin it down.
Ovulation is usually about 14 days before the next period, so in a 29-day cycle it falls on day 15 — 1 day later than in a 28-day cycle. A 29-day cycle is within the usual adult range of about 21–35 days.
Your 29-day cycle, phase by phase
| Phase | Cycle days |
|---|---|
| Period (typical) | Days 1–5 |
| Follicular phase | Days 1–14 (14 days) |
| Fertile window | Days 10–16, best on days 13–15 |
| Ovulation | Day 15 |
| Luteal phase | Days 16–29 (14 days) |
Start LH ovulation tests around day 12; a positive result on day 13 or 14 points to ovulation on day 15.
If your cycle is sometimes 27 or 31 days
Few cycles are identical every month. If yours ranges between 27 and 31 days, ovulation could fall anywhere from day 13 to day 17, which widens your possible fertile days to days 8 to 18. Base the start of ovulation testing on your shortest recent cycle (day 10), and expect your period between day 28 and day 32.
| Cycle length | Ovulation | Fertile window |
|---|---|---|
| 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 |
| 31 days | Day 17 | Days 12–18 |
Example: a 29-day cycle starting today
| Period starts (day 1) | |
|---|---|
| Start ovulation tests (day 12) | |
| Fertile window (days 10–16) | – |
| Estimated ovulation (day 15) | |
| Next period / test day (day 30) |
Test for pregnancy from day 30 — see the Pregnancy Test Calculator for exact dates.