Period Calendar
Next periods, fertile days and ovulation for the coming months.
These are estimates based on standard formulas, not medical advice.
| Period starts | Period ends | Fertile window | Ovulation |
|---|---|---|---|
| Oct 29, 2026 | Nov 2, 2026 | Oct 10, 2026 – Oct 16, 2026 | Oct 15, 2026 |
| Nov 26, 2026 | Nov 30, 2026 | Nov 7, 2026 – Nov 13, 2026 | Nov 12, 2026 |
| Dec 24, 2026 | Dec 28, 2026 | Dec 5, 2026 – Dec 11, 2026 | Dec 10, 2026 |
| Jan 21, 2027 | Jan 25, 2027 | Jan 2, 2027 – Jan 8, 2027 | Jan 7, 2027 |
| Feb 18, 2027 | Feb 22, 2027 | Jan 30, 2027 – Feb 5, 2027 | Feb 4, 2027 |
| Mar 18, 2027 | Mar 22, 2027 | Feb 27, 2027 – Mar 5, 2027 | Mar 4, 2027 |
Runs entirely in your browser. Nothing is sent anywhere.
How it works
- 1Enter your values.
- 2See the result update instantly as you type.
- 3Change any value to compare scenarios.
About this tool
Period Calendar: Next periods, fertile days and ovulation for the coming months. Type your numbers and the result is calculated instantly — no button to press, nothing to install. All math runs locally in your browser, so the values you enter are never sent anywhere.
Example
| Period starts | Period ends | Fertile window | Ovulation |
|---|---|---|---|
| Oct 29, 2026 | Nov 2, 2026 | Oct 10, 2026 – Oct 16, 2026 | Oct 15, 2026 |
| Nov 26, 2026 | Nov 30, 2026 | Nov 7, 2026 – Nov 13, 2026 | Nov 12, 2026 |
| Dec 24, 2026 | Dec 28, 2026 | Dec 5, 2026 – Dec 11, 2026 | Dec 10, 2026 |
| Jan 21, 2027 | Jan 25, 2027 | Jan 2, 2027 – Jan 8, 2027 | Jan 7, 2027 |
| Feb 18, 2027 | Feb 22, 2027 | Jan 30, 2027 – Feb 5, 2027 | Feb 4, 2027 |
| Mar 18, 2027 | Mar 22, 2027 | Feb 27, 2027 – Mar 5, 2027 | Mar 4, 2027 |
How do I use the Period Calendar?
Enter your values. See the result update instantly as you type. Change any value to compare scenarios.
Is the Period Calendar free?
Yes. It is completely free with no sign-up, no usage limits and no watermark.
Is my data sent to a server?
No. Everything is calculated locally in your browser. Nothing you enter is uploaded, logged or stored.
Does it work on my phone?
Yes. It works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux — no app needed.