Pregnancy Calculator
Estimate due dates and pregnancy milestones based on LMP, conception, ultrasound, or IVF data.
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How to Use the Pregnancy Calculator
Pregnancy is a very unique and private experience, and knowledge of key dates and milestones can help expecting parents feel more educated and ready for any situation. The Pregnancy Calculator calculates your estimated due date and monitors your pregnant months by recognized medical calculations. The given calculator will help you calculate a gestation period according to various dates such as the first day of the last menstrual period (LMP), the date of conception, dates of ultrasound measurements, dates of IVF transfer, as well as other dates. Because it is hard to pinpoint the conception dates accurately, a standardized approach is used by medical professionals. This is more of a guide so that you do not have a specific date, but rather an approximate window during which your due date is, and other important milestones that you are expected to reach during pregnancy. If you are pregnant for the first time or monitoring your pregnancy progress, this calculator will provide you with an accurate idea of your progress.
How to Use
1. Choose the Calculation Method
First, select how you will calculate your pregnancy timeline: from LMP, conception date, ultrasound data, or your IVF transfer date. Different methods are useful depending on the information that one has.
2. Enter the Relevant Date
Give the date that corresponds to your chosen method, such as the first date of your last menstrual period or the date of embryo transfer. Precise dates lead to better results when estimates are made.
3. Select Average Cycle Length (If Applicable)
If you are using the LMP date method, you can then enter your average menstrual cycle length.
4. Calculate Pregnancy Timeline
Once all inputs have been entered, calculate to see your estimated due date, current gestational age, and pregnancy milestones.
5. Use Results as a Guideline
Consider the calculated dates to be estimates. Not all pregnancies have the same length, and actual delivery may happen prior to or after those dates.
Key Formulas Used
Naegele’s Rule is the most commonly used method to estimate pregnancy due dates based on the first day of the last menstrual period.
This method estimates pregnancy length from the estimated date of conception rather than menstrual cycles.
For IVF pregnancies, calculations are adjusted based on embryo age at transfer to align with standard gestational timelines.
Benefits
- Estimates pregnancy due date using multiple methods
- Tracks gestational age and pregnancy progress
- Supports planning and milestone awareness
- Uses medically accepted calculation approaches
- Easy to use and understand
- Helpful throughout all pregnancy stages
- Provides clarity without medical jargon
When & Where to Use
- Estimating pregnancy due date
- Tracking pregnancy milestones
- Planning prenatal appointments
- Understanding gestational age
- Supporting IVF pregnancy tracking
- Monitoring trimester progression
- General pregnancy awareness
Who Should Use This Calculator
The Pregnancy Calculator is appropriate for those pregnant or planning to conceive and wishing to have a general idea of their dates. In a natural conception, or with the aid of reproduction biotechnologies such as IVF, or with ultrasound date estimation, it can be used in any stage of pregnancy.
Related Calculators
What is this?
A pregnancy calculator estimates your due date and tracks pregnancy progress using your LMP, due date, conception, ultrasound, or IVF date.
How it works
It applies Naegele's rule (adding 280 days to the last menstrual period) or equivalent adjustments for other calculation types.
Pro Tips
- Due dates are estimates — only 5% of babies are born exactly on that day.
- Full-term pregnancy is 37–42 weeks.
- Consult your doctor for personalized medical advice.
Frequently Asked Questions
How accurate is the pregnancy due date?
The calculated due date is an estimate. Only about 5% of babies are born on their exact due date. Most pregnancies last between 37 and 42 weeks.
What is LMP and why is it used?
LMP stands for Last Menstrual Period. It is commonly used to estimate pregnancy duration because ovulation and conception dates are often uncertain.
Can ultrasound dating change my due date?
Yes. Early ultrasounds, especially in the first trimester, can provide a more accurate gestational age and may adjust the estimated due date.
How is pregnancy calculated for IVF?
For IVF pregnancies, calculations are based on the embryo transfer date and embryo age (day 3, 5, or 6), then adjusted to align with standard gestational age counting.
What does full-term pregnancy mean?
A full-term pregnancy typically ranges from 37 to 42 weeks. Babies born before 37 weeks are considered preterm.