Ovulation Calculator
Fertile window and ovulation dates for the next cycles.
- Next period
- Thu, November 26, 2026
| Cycle | Ovulation | Fertile window | Next period |
|---|---|---|---|
| Cycle 1 | Nov 12 | Nov 7 to Nov 13 | Nov 26 |
| Cycle 2 | Dec 10 | Dec 5 to Dec 11 | Dec 24 |
| Cycle 3 | Jan 7 | Jan 2 to Jan 8 | Jan 21 |
Cycle timing varies. Ovulation tests or tracking basal temperature give more precise results.
How this calculator works
Ovulation usually happens about 14 days before the next period. The fertile window covers the five days before ovulation and the day after.
Formula
Ovulation ≈ LMP + cycle length − 14 days
Example
With a period starting March 1 and a 28-day cycle, ovulation is around March 15 and the fertile window runs March 10 to 16.
When to use it
- Planning conception
- Understanding your cycle
- Preparing for fertility appointments
Frequently asked questions
When am I most fertile?
The two to three days before ovulation and the day of ovulation carry the highest chance of conception.
Does this work with irregular cycles?
Predictions are less reliable when cycle length varies. Ovulation test kits or tracking basal body temperature can pinpoint ovulation more accurately.
Offers from our partners
Smart body scales
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Meal planning apps
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Fitness trackers
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Learn more
How to calculate ovulation and find your fertile window
How to estimate when you ovulate from your cycle, which days are most fertile, and how to confirm it with tests and body signs.
How is a due date calculated? From last period, conception or IVF
A due date feels like a deadline but is really the middle of a window. Here is exactly how it is worked out.