Conception Calculator
Estimate a possible conception window and corresponding due date.
Estimated fertile window: July 29, 2026 to August 4, 2026.
If conception occurs near this estimate, the due date is approximately April 26, 2027.
How to use this calculator
- Enter a period start date and usual cycle length.
- Review the live result and use Copy result when you need to share it.
How the calculation works
The same cycle-based ovulation approximation identifies a possible window and adds 266 days for a corresponding due-date estimate.
Formula
The same cycle-based ovulation approximation identifies a possible window and adds 266 days for a corresponding due-date estimate.
Step-by-step calculation
- Enter a period start date and usual cycle length.
- The same cycle-based ovulation approximation identifies a possible window and adds 266 days for a corresponding due-date estimate.
- Check the displayed result, then copy it if needed.
Worked example
A 28-day cycle estimates ovulation around day 14, but real cycles vary.
Risk guidance
Frequently asked questions
Does this tool send my inputs anywhere?
No. The interactive calculation runs in your browser and this site does not submit tool inputs to a backend.
How should I use the result?
Check that the entered units and values match your situation, especially around dates, breaks, and rounding.
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