Ovulation Calculator
Your fertile days and ovulation date
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 |
- 1Enter your last periodThe first day of bleeding
- 2Set your cycle length28 days if you're not sure
- 3See fertile daysFor the next six cycles
How is ovulation predicted?
Ovulation usually happens about 14 days before the next period starts. The fertile window is the 5 days before ovulation plus the day after.
Ovulation ≈ next period − 14 days
Fertile window = ovulation − 5 days to ovulation + 1 day
Irregular cycles
If your cycle length changes from month to month, predictions are less reliable. Ovulation test kits, basal body temperature or cervical mucus tracking can help pinpoint it.
Using this to avoid pregnancy
Calendar predictions aren't reliable contraception. Talk to a doctor about safer options.
Related calculators
Frequently asked questions
What are my most fertile days?
The 2–3 days before ovulation and the day of ovulation itself. The calculator shows the full 6-day window.
Can I get pregnant outside the fertile window?
It's unlikely but possible, especially with irregular cycles, because ovulation can come earlier or later than predicted.
How long is a normal cycle?
Anything from about 21 to 35 days is common in adults.
Sources
Last reviewed: October 2026