Ovulation Calculator

Estimate your ovulation date, fertile window and next period from your cycle. Free, private ovulation calendar.

✓ 100% free ✓ No sign up ✓ Runs in your browser — nothing uploaded

First day of last period

Cycle length (days)

Estimated ovulation

Friday, November 6, 2026

Fertile window 11/1/2026 – 11/7/2026

Next period Friday, November 20, 2026

Ovulation in 1 cycle 12/4/2026

Ovulation in 2 cycles 1/1/2027

Note Estimate only — not a contraceptive method

How to use Ovulation Calculator

Is Ovulation Calculator free?

Yes. Ovulation Calculator is 100% free with no limits, no watermark, no sign up and no email required.

Is my data sent anywhere?

No. Everything is calculated locally in your browser. Nothing you type is sent to or stored on any server.

Does Ovulation Calculator work on my phone?

Yes. Ovulation Calculator works in any modern browser on iPhone, Android, Windows, Mac, Linux and Chromebook. No app or install needed.

Do I need to create an account?

Never. There is no sign up, no login, no email and no paywall. Just open the page and use it.

How accurate is it?

Calculations use standard formulas with full floating-point precision. For medical, legal or financial decisions, please confirm with a professional.