Ovulation & Fertile Window Calculator
Calculator ToolsOvulation day, fertile days and next period
Embed this tool on your websiteFree
- Choose how tall the frame should be.
- Press Copy code.
- Paste it into your page, blog, WordPress or Notion HTML block.
The tool runs inside your visitor's browser, nothing is uploaded, and a small "Powered by ToolCloak" line stays under it. The second line (script) is optional: it makes the frame fit the tool's height.
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History
All history →Ovulation & Fertile Window Calculator — at a glance
Plan better by finding the days you are most likely to be fertile.
How to use it — step by step
The first day of your last period, your usual cycle length and luteal phase.
Enter your numbers
Fill in the fields — sensible example values are already filled in.
Pick your options
Choose any dropdowns or switches that apply to your case.
Calculate Ovulation
Press the button. The result is created instantly on your device.
Read the answer
The main answer is shown big at the top, with details below it.
Pro tips
Small things that make the result better.
Quick facts
Frequently Asked Questions
How is ovulation estimated?+
Ovulation usually happens about 14 days before the next period starts.
Is this a contraception tool?+
No. Do not rely on it to avoid pregnancy.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.