Pregnancy 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 Pregnancy Calculator works
Estimate gestational age, trimester and due date from the last menstrual period. Enter the requested values in the tool above, select Calculate, and review both the main result and its breakdown.
Formula used
Estimated due date = first day of the last menstrual period + 280 days. Gestational age is elapsed time from that date.
Worked example
Cycle variation, ultrasound dating and clinical factors may change a due date.
Practical uses
- Estimate gestational age
- View an approximate trimester
- Prepare for a prenatal appointment
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.