Pregnancy
When Do You Ovulate? How to Find Your Fertile Window
Count back 14 days from your next period, a fertile-window chart by cycle length, and the body signs that confirm ovulation.
By Team Vind · Updated · 5 min read
You can get pregnant on only about six days of each cycle: the five days before ovulation and the day of ovulation itself. Calculators usually add the day after as a buffer, since ovulation can come a day late. Knowing when those days fall is the single most useful thing you can do when trying to conceive. Here's how to work out your fertile window from your cycle length, and how to confirm it.
When do you ovulate?
The part of your cycle after ovulation (the luteal phase) is fairly fixed at about 14 days. The part before it varies. So count back 14 days from your next period, not forward 14 days from the last one.
Ovulation day ≈ cycle length − 14 · fertile window = 5 days before ovulation to 1 day after
Example: a 28-day cycle with the period starting 2 November 2026. Ovulation is around 16 November 2026, and the fertile window runs from 11 November 2026 to 17 November 2026. The next period is due on 30 November 2026.
Fertile window by cycle length
| Cycle length | Ovulation (cycle day) | Fertile window for a 2 November period |
|---|---|---|
| 24 days | Day 10 | 7 November – 13 November |
| 26 days | Day 12 | 9 November – 15 November |
| 28 days | Day 14 | 11 November – 17 November |
| 30 days | Day 16 | 13 November – 19 November |
| 32 days | Day 18 | 15 November – 21 November |
| 35 days | Day 21 | 18 November – 24 November |
Try it: Ovulation Calculator
Your Fertile Window
Next six cycles
| Period starts | Fertile window | Ovulation |
|---|---|---|
| 30 September 2026 | 9 October 2026 – 15 October 2026 | 14 October 2026 |
| 28 October 2026 | 6 November 2026 – 12 November 2026 | 11 November 2026 |
| 25 November 2026 | 4 December 2026 – 10 December 2026 | 9 December 2026 |
| 23 December 2026 | 1 January 2027 – 7 January 2027 | 6 January 2027 |
| 20 January 2027 | 29 January 2027 – 4 February 2027 | 3 February 2027 |
| 17 February 2027 | 26 February 2027 – 4 March 2027 | 3 March 2027 |
Why the window starts before ovulation
Sperm can survive up to five days in the body, but an egg lives only about 12 to 24 hours after it's released. So sex in the days before ovulation gives the best chance: the two days before ovulation and the day itself are the most fertile.
Confirm it with your body's signs
- Ovulation test strips detect the LH surge, which comes 24–36 hours before ovulation. Start testing a few days before the expected date.
- Cervical mucus becomes clear, slippery and stretchy, like raw egg white, in the fertile days.
- Basal body temperature rises by about 0.2–0.5 °C after ovulation. It confirms ovulation has happened, which helps you learn your pattern over a few months.
When to see a doctor
Most couples conceive within a year. See a doctor after 12 months of regular unprotected sex without pregnancy, or after 6 months if the woman is 35 or older, and sooner if periods are very irregular or absent.
Pregnant already? Find out how your due date is calculated. Tracking your periods? Try the period calculator.
Frequently asked questions
How many days after my period do I ovulate?
Count from the first day of your period: ovulation is around day (cycle length − 14). In a 30-day cycle that's day 16.
Can I get pregnant right after my period?
It's possible with short cycles. In a 24-day cycle ovulation is around day 10, so the fertile window can start on day 5.
How accurate are ovulation calculators?
They're a good estimate for regular cycles. Ovulation test strips and cervical mucus changes confirm the actual timing.
Can you ovulate without a period?
Ovulation comes before a period, so it can happen, for example while breastfeeding or after stopping the pill. Irregular or missing periods should be checked by a doctor.
Sources
- Wilcox AJ et al. Timing of sexual intercourse in relation to ovulation. N Engl J Med, 1995
- American College of Obstetricians and Gynecologists: Evaluating infertility (FAQ)
Last reviewed: 10 October 2026