How this calculation works
Use this pregnancy due date calculator to estimate a due date from the first day of a last menstrual period (LMP). The common estimate adds 280 days, or 40 weeks, to the LMP. Pregnancy dating can change after an ultrasound or clinical review, so keep routine prenatal appointments and follow your care team.
Mathematical formula and logic
Estimated due date = first day of LMP plus 280 days.
Worked example
An LMP of 1 June 2026 produces an estimated due date around 8 March 2027.
Calculation assumptions
- The estimate assumes a typical 28-day cycle.
- Ovulation timing can vary substantially.
- Ultrasound dating may change the estimated due date.
- This tool is not a substitute for prenatal care.
Frequently asked questions
What does the Pregnancy Due Date Calculator calculate?
The Pregnancy Due Date Calculator turns the values you enter into a practical estimated due date estimate. It is designed for global and india planning, so you can test several scenarios before relying on a provider, official form, or professional assessment.
Which inputs affect the Pregnancy Due Date Calculator most?
The inputs shown above are used directly in the calculation. Change one value at a time to see its effect, then compare a conservative scenario with your best estimate. Important decisions should be checked against source documents and current provider rules.
Can I use this Pregnancy Due Date Calculator on mobile?
Yes. The tool runs in the browser and is designed for phone, tablet, and desktop use. You can reset the fields or copy a shareable result link after testing the values that matter to you.
Are results from the Pregnancy Due Date Calculator official?
No. This is an educational estimate based on the assumptions displayed on the page. A lender, tax authority, doctor, employer, school, or service provider can apply additional rules that change the final outcome.
How should I use the Pregnancy Due Date Calculator result?
Use the result as a starting point for a decision, not as the decision itself. Save the scenario, compare it with a related CalculatorAll.online tool, and confirm material financial, tax, medical, or legal details with the relevant qualified professional or official source.