Due Date Calculator
Your entries are calculated in this browser and are not saved by this tool.
This result is an estimate and does not diagnose, prevent or treat any condition. Consult a qualified health professional.
How the Due Date Calculator works
Estimate a pregnancy due date from a last period or conception date. Enter the requested values in the tool above, select Calculate, and review both the main result and its breakdown.
Formula used
Last menstrual period adds 280 days; a known conception date adds 266 days.
Worked example
An LMP of January 1, 2024 gives an estimated due date of October 7, 2024.
Practical uses
- Estimate a calendar date
- Compare dating methods
- Plan a prenatal discussion
Assumptions and limits
Health results are screening estimates, not a diagnosis. Individual needs and clinical circumstances can differ. For reproducibility, record the inputs and assumptions used when sharing a result.
Frequently asked questions
Is this calculator free?
Yes. It can be used without creating an account.
Are the values I enter stored?
The calculation runs in your browser. The core tool does not submit your calculator entries to WordPress.
Can I rely on the result for a major decision?
Use it as an educational estimate, verify important inputs, and seek qualified advice when the decision carries financial, medical, tax or legal consequences.