Educational content, not medical advice. Clinical review of this page is in progress.
Common questions about how our calculators work and how accurate they are.
Frequently Asked Questions
How accurate are PregCalc’s calculators?
Our calculators use standard clinical formulas (like Naegele’s rule) used across the medical field, but they’re estimates — always confirm key dates with your provider.
Do I need to create an account to use the calculators?
No, all PregCalc calculators are free to use without an account.
Which calculator should I use if I’m not sure of my last period?
Try the conception-date or ultrasound-based options where available, or ask your provider to date your pregnancy directly.
How accurate are the calculators
They give estimates based on the dates you enter and standard averages. Real pregnancies vary, so always confirm with your provider.
Which calculator should I use first
If you are trying to conceive, use the Ovulation Calculator. If pregnant, use the Due Date Calculator. See every tool in All Tools.
Why does my due date differ from my doctor’s
Providers may adjust the date using ultrasound; see when and why gestational age gets adjusted.
Related Resources
- Pregnancy FAQs
- Gestational Age: Frequently Asked Questions
- Pregnancy Terms Glossary
- All Pregnancy & Fertility Calculators
Sources and Further Reading
This page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your OB-GYN or midwife about your own pregnancy.