How to use
- Open Baby Due Date & Gestational Age Calculator and enter the fields shown in the form.
Baby Due Date & Gestational Age Calculator
Calculate your baby's expected due date and gestational age based on your last menstrual period.
Parent guide
How to use this tool
Calculate your baby's expected due date and gestational age based on your last menstrual period.
What the result means
Calculate your baby's expected due date and gestational age based on your last menstrual period.
Method
Estimated due date from LMP plus 280 days, adjusted for cycle length
Worked example
Important limitation
Ultrasound dating and clinician assessment may revise the estimate, especially with uncertain LMP or irregular cycles.
Primary sources
References and data notes
Safety note
Use this result for planning and conversation. If symptoms, unusual growth changes, feeding problems, pregnancy concerns, or urgent health questions arise, contact a qualified healthcare professional.
Frequently asked questions
Which sources and method does this tool use?
The method, version and primary sources are listed in the evidence section above.
When should I use Baby Due Date & Gestational Age Calculator?
Use it when you want a quick educational estimate for: Calculate your baby's expected due date and gestational age based on your last menstrual period.
What affects the Baby Due Date & Gestational Age Calculator result?
The result depends on the age, dates, measurements, units, reference choice, and assumptions shown in the form.