Ovulation in a 25-day cycle: day 11
With ovulation around day 11, a 25-day cycle is short but very common. Start ovulation tests on about day 8 so that an early LH surge is not missed.
A pregnancy test becomes reliable from day 26 — about three days earlier than for someone with a 28-day cycle.
Ovulation is usually about 14 days before the next period, so in a 25-day cycle it falls on day 11 — 3 days earlier than in a 28-day cycle. A 25-day cycle is within the usual adult range of about 21–35 days.
Your 25-day cycle, phase by phase
| Phase | Cycle days |
|---|---|
| Period (typical) | Days 1–5 |
| Follicular phase | Days 1–10 (10 days) |
| Fertile window | Days 6–12, best on days 9–11 |
| Ovulation | Day 11 |
| Luteal phase | Days 12–25 (14 days) |
Start LH ovulation tests around day 8; a positive result on day 9 or 10 points to ovulation on day 11.
If your cycle is sometimes 23 or 27 days
Few cycles are identical every month. If yours ranges between 23 and 27 days, ovulation could fall anywhere from day 9 to day 13, which widens your possible fertile days to days 4 to 14. Base the start of ovulation testing on your shortest recent cycle (day 6), and expect your period between day 24 and day 28.
| Cycle length | Ovulation | Fertile window |
|---|---|---|
| 23 days | Day 9 | Days 4–10 |
| 24 days | Day 10 | Days 5–11 |
| 25 days | Day 11 | Days 6–12 |
| 26 days | Day 12 | Days 7–13 |
| 27 days | Day 13 | Days 8–14 |
Example: a 25-day cycle starting today
| Period starts (day 1) | |
|---|---|
| Start ovulation tests (day 8) | |
| Fertile window (days 6–12) | – |
| Estimated ovulation (day 11) | |
| Next period / test day (day 26) |
Test for pregnancy from day 26 — see the Pregnancy Test Calculator for exact dates.