Conception Date Calculator
Estimate conception date or range from LMP, due date or ovulation and clearly label the chosen method.
Enter or adjust the values above, then calculate.
Conception Date: estimate from LMP, Due Date or Ovulation
Estimate conception date or range from LMP, due date or ovulation and clearly label the chosen method.
Inputs this tool uses
- Known date
- Date
What you get
Estimated conception date from the selected dating basis.
How to use the Conception Date Calculator
- Enter known date, date.
- Select any method, activity level or option shown on this page, then choose Calculate.
- Read the main result together with the supporting values, method, assumptions and limitations below before using the estimate.
How this calculation works
Cycle tools use date arithmetic from observed period starts and user-entered cycle assumptions. Estimates are never presented as contraception.
Example calculation
The sample values loaded into the calculator produce 2026-10-09. This example exists to show how the output is structured; replace the sample values with your own inputs for your calculation.
Assumptions and limitations
- Cycle and ovulation dates are estimates and can vary from cycle to cycle.
- This tool is not contraception and does not diagnose fertility or pregnancy.
Sources and review status
Source set last verified 2026-09-25. No clinician review is claimed unless a real named reviewer is displayed.
Connected tools
Continue with the closest related calculation without re-entering sensitive values automatically.
Estimate ovulation from the expected next period minus an editable luteal-phase assumption and show the assumption used.
Open tool →◌Fertile Window CalculatorEstimate a broad fertile window around ovulation and explicitly state that the result is not contraception.
Open tool →◌Luteal Phase CalculatorCalculate luteal-phase length from an observed/estimated ovulation date and next period start.
Open tool →