Due Date Calculator
Estimate a pregnancy due date from the first day of the last menstrual period or a known conception date.
Calculator workspace
Enter your values, then calculate to see the result and supporting figures.
How This Due Date Calculator Works
Estimate a pregnancy due date from the first day of the last menstrual period or a known conception date. The rebuilt page uses calculator-specific logic rather than the legacy page script. Inputs are validated before calculation, and supporting figures are shown with the headline result so the arithmetic is easier to check.
Core method: From LMP: estimated due date = LMP + 280 days. From conception: estimated due date = conception + 266 days.
How to Use It
- Enter the values requested in the calculator workspace.
- Select Calculate and correct any input highlighted by validation.
- Review the main answer, supporting figures and formula/method shown with the result.
- Use Copy Result, Share Result or Save Result Image if you need to keep the calculation.
Worked Example
An LMP date is conventionally projected 280 days forward for an estimated due date.
Common Uses
- Pregnancy date estimates
- Calendar planning
- Appointment preparation
Common Search Questions About Due Date Calculator
How do I calculate this?
Estimate a pregnancy due date from the first day of the last menstrual period or a known conception date.
What formula does this calculator use?
From LMP: estimated due date = LMP + 280 days. From conception: estimated due date = conception + 266 days.
How can I get the result quickly?
Enter the required values and select Calculate. The rebuilt mobile interface brings the result into view instead of leaving it far below the form.
Important Limitations
Pregnancy dating is an estimate and can change after clinical assessment or ultrasound. This is not medical advice; use a healthcare professional for pregnancy care.
Frequently Asked Questions
Does the calculator upload my inputs?
No. The calculation runs in the browser and does not require an account.
Can I calculate again with different values?
Yes. Change any input and calculate again to compare scenarios.
Should I verify important results?
Yes. For high-impact financial, legal, health, engineering or contractual decisions, compare calculator output with current source information and appropriate professional guidance.