Ovulation in a 33-day cycle: day 19
In a 33-day cycle, ovulation around day 19 comes after a long follicular phase, while the time from ovulation to your period stays about two weeks.
Begin ovulation tests around day 16; a pregnancy test is reliable from day 34.
Ovulation is usually about 14 days before the next period, so in a 33-day cycle it falls on day 19 — 5 days later than in a 28-day cycle. A 33-day cycle is within the usual adult range of about 21–35 days.
Your 33-day cycle, phase by phase
| Phase | Cycle days |
|---|---|
| Period (typical) | Days 1–5 |
| Follicular phase | Days 1–18 (18 days) |
| Fertile window | Days 14–20, best on days 17–19 |
| Ovulation | Day 19 |
| Luteal phase | Days 20–33 (14 days) |
Start LH ovulation tests around day 16; a positive result on day 17 or 18 points to ovulation on day 19.
If your cycle is sometimes 31 or 35 days
Few cycles are identical every month. If yours ranges between 31 and 35 days, ovulation could fall anywhere from day 17 to day 21, which widens your possible fertile days to days 12 to 22. Base the start of ovulation testing on your shortest recent cycle (day 14), and expect your period between day 32 and day 36.
| Cycle length | Ovulation | Fertile window |
|---|---|---|
| 31 days | Day 17 | Days 12–18 |
| 32 days | Day 18 | Days 13–19 |
| 33 days | Day 19 | Days 14–20 |
| 34 days | Day 20 | Days 15–21 |
| 35 days | Day 21 | Days 16–22 |
Example: a 33-day cycle starting today
| Period starts (day 1) | |
|---|---|
| Start ovulation tests (day 16) | |
| Fertile window (days 14–20) | – |
| Estimated ovulation (day 19) | |
| Next period / test day (day 34) |
Test for pregnancy from day 34 — see the Pregnancy Test Calculator for exact dates.