---
title: Ovulation Calculator: When Do I Ovulate?
description: Free ovulation calculator. Estimate your ovulation day, fertile window, luteal phase and PMS window from your last period and cycle length.
url: https://niyora.com/tools/ovulation-calculator/
---

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- Ovulation calculator: when do I ovulate?

Free tool

# Ovulation calculator: when do I ovulate?

An estimate of your ovulation day for the next three cycles, about 14 days before each period, plus the luteal phase and PMS window that follow.

Loading the calculator…

## How ovulation is estimated

Ovulation usually happens about **14 days before your next period**, not 14 days after your last one. In a 28-day cycle those are the same day. In a 32-day cycle, ovulation is closer to day 18. The calculator counts back from your next predicted period.

This is an estimate. It isn’t reliable enough to use as contraception.

## Can ovulation affect your mood?

Yes, for some people. Estrogen peaks just before ovulation, and many feel more energetic and social then. For people with PMDD, symptoms can start right after ovulation as progesterone rises. If your hard days start mid-cycle, that’s worth tracking and telling a doctor.

When the window arrives

Niyora predicts your PMS window from your own cycles, then helps with the hard moment itself.

## Questions people ask

Can I ovulate a week before my period?

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It’s uncommon. Ovulation is usually 12 to 14 days before a period. A gap of only a week would mean a very short luteal phase, which is worth checking with a doctor if it happens often.

Can ovulation cause mood swings?

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Some people notice mood changes around ovulation, and in PMDD symptoms often begin after it. Tracking a few cycles shows whether your mood follows that pattern.

## More free tools

[PMS calculator: see when your hard days start](https://niyora.com/tools/pms-calculator/)[Period calculator: when is my next period?](https://niyora.com/tools/period-calculator/)[Luteal phase calculator](https://niyora.com/tools/luteal-phase-calculator/)

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