Pregnancy Calculator
Fast, accurate and free online pregnancy calculator tool running directly in your browser.
-
1Enter data
Enter content, paste text or load a file from disk. -
2Click the button
The tool will immediately process your data in the browser. -
3Get the result
Copy the finished text or save the file to your device.
return "Result ready in 0.1s";
}
Pregnancy and Due Date Calculator
Calculate your due date, gestational age and learn about the most important dates of your baby's development. Precise algorithm taking into account the cycle length.
Input
Fill in details to see the magic
You'll find out when you welcome your baby, what his zodiac sign is and how big he is now.
Rate this tool:
Related tools
Other tools you may find usefulPregnancy and due date calculator - weeks of pregnancy, trimesters and important dates
The online pregnancy calculator helps you quickly calculate yourexpected due date(TP), currentgestational agein weeks and days, and organize the most important dates in your pregnancy calendar - without guesswork, without manual counting and without stress. Just enterthe date of the first day of the last menstrual period (OM)and - optionally -the cycle lengthfor the tool to calculate the due date using a method based on standard obstetric assumptions. Additionally, you receive a clear report: pregnancy percentage progress, trimester, estimated date of conception, full-term pregnancy window and a set of "milestones" (e.g. the end of the first trimester, around the mid-term ultrasound or the survival limit).
What exactly does the pregnancy calculator calculate?
- Expected due date (EDD/TP):date based on OM and cycle length.
- Gestation age:number of complete weeks and additional days (e.g. 18 weeks and 3 days).
- Trimester:automatic information whether you are in the 1st, 2nd or 3rd trimester.
- Pregnancy Progress:in percentage to easily "see" the stage you are at.
- Estimated date of conception:approximation based on standard ovulation assumptions.
- Full-Term Pregnancy Window:the range of dates in which a birth is considered full-term.
- Event Calendar:an ordered list of the most frequently referenced pregnancy milestones.
Who is the due date calculator for?
The pregnancy calculator is used by future mothers (and their loved ones) who want to quickly check the due date and pregnancy age without looking through the calendar, counting the weeks on their fingers or wondering which trimester it is. The tool is also useful in everyday planning: setting approximate dates for tests, holidays, follow-up visits, completing the layette or simply tracking the progress of pregnancy in a more "tangible" way.
If you have a regular cycle – the calculator will usually give you a very reasonable reference point. If the cycle is irregular, there are large fluctuations in the cycle length or you do not remember the exact date of OM - treat the result as an approximation and rely on the information from the ultrasound and the doctor's/midwife's recommendations.
How the pregnancy calculator works - simple and without secrets
In obstetrics, the starting point for calculations is usuallythe first day of the last menstrual period (OM). The standard length of pregnancy calculated using this method is approximately280 days(40 weeks), which results from the classic assumptions: ovulation and fertilization occur on average around the 14th day of a 28-day cycle. Since cycles can have different lengths, a good calculator takes into account the possibility of correction - which is why in this tool you can entercycle length. Thanks to this, the due date is moved according to the difference from the 28-day cycle.
OM(last menstrual period) is the most important entry date. It determines the age of pregnancy, trimesters and the base date of delivery. If you are not sure about the OM date, the result will be less accurate.
Cycle lengthallows you to adjust the calculations. In a longer cycle, ovulation often occurs later, and in a shorter cycle, earlier, so the due date may be slightly postponed.
Reference dateis optional. If you enter it, the calculator will calculate the gestational age on a specific day (e.g. "on the day of the examination" or "on the date of the visit"). If left blank, it counts "for today".
Trimesters – what do they mean and why are they in the report?
Dividing pregnancy into trimesters is practical: it helps describe the baby's stage of development, typical symptoms and care priorities. In short:I trimesteris a time of dynamic changes and often the greatest fluctuations in well-being,II trimesteris sometimes described as "more stable", andIII trimesteris preparing the body for childbirth. The calculator shows the trimester automatically because it is quick information that makes it easier to interpret the week of pregnancy and plan tests.
What does "full-term pregnancy" and the delivery window mean?
In everyday language, we say "full-term pregnancy" when delivery occurs during the period considered safest for the baby. The calculator shows the range of dates that constitute thefull-term pregnancy window- that is, the time frame in which the pregnancy is treated as full-term (in the broad sense).
This is not a "guaranteed date" or a promise that labor will begin at that exact time. This is rather practical information: statistically, when does labor most often begin and when is a full-term pregnancy considered? Many babies are born a few days before or after TP - and this is still within the norm.
Estimated date of conception - why is it "approximate"?
In the calculator, the date of conception is estimated based on the classic assumption that ovulation occurs around the middle of the cycle. In practice, ovulation may occur earlier or later, and the cycle may vary depending on stress, illness, travel and other factors. Therefore, thedate of conception is indicative- it can help with curiosity and general orientation, but should not be taken for granted.
If you want to date your pregnancy more precisely, the most reliable way is to estimate the gestational age based on ultrasound, especially in early pregnancy. However, the calculator has one huge advantage: it quickly and clearly organizes your calendar when you need a simple reference point.
Pregnancy calendar – milestones in one place
One of the most practical elements of the tool is themilestone table. Instead of wondering “when does the first trimester end?” or "in what week is the mid-ultrasound?", you get a list ordered chronologically. This saves time and helps you plan visits and tests. It is worth remembering that specific test dates may vary depending on the doctor's recommendations, the course of pregnancy and the standards of a specific facility, but arranging the dates in a timeline can be very reassuring - because it gives a sense of control and predictability.
| Report element | What is | Why is it useful |
|---|---|---|
| Due date (TP) | Estimated due date | Planning and orientation, "reference point" in the calendar |
| Pregnancy age | Weeks + days | Conversations with doctor/midwife, interpretation of weekly recommendations |
| Trimester | Stage of pregnancy (I/II/III) | Easier understanding of body changes and care priorities |
| Term window | Date range for full-term delivery | Realistic preparation for childbirth |
| Milestones | List of important moments | Order and peace - "what and when" in one place |
How to use the calculator - step by step
- Enterthe date of the first day of your last menstrual period (OM)in the date field.
- Setcycle length(if you don't know - leave 28 days). The tool will adjust the due date.
- Optionally, enterreference dateif you want to count the gestational age "as of a specific date".
- ClickCalculate due dateand see the result: TP, weeks and days of pregnancy, trimester, progress and calendar.
- If you want to start over, useClear.
Frequently asked questions and doubts
- "I have an irregular cycle"- treat the result as approximate and compare it with the ultrasound dating.
- "I don't remember the exact OM"- try to estimate and note that this is an approximation; later, ultrasound is what counts anyway.
- “Result varies from doctor to doctor”– this is normal; the doctor may rely on ultrasound and CRL measurements.
- "I'm overdue"- this is often still a variant of the norm; monitoring is determined by medical staff.
- “Is this tool accurate?”– is good for orientation, but does not replace medical care.
What should you prepare after calculating the result?
When you know the due date and gestational age, it is much easier to plan practical things: holidays, preparing a layette, schedule of tests, and even simple "windows" for rest and regeneration. For many people, the greatest value is organizing in their heads: "where I am on the timeline and what awaits me."
FAQ - Pregnancy and due date calculator
Is the due date from the calculator "certain"?
No. The due date isestimatedand is based on statistical assumptions. Babies are often born a few days before or after TP. More accurate dating may result from ultrasound, especially in the first trimester.
Why does cycle length matter?
To put it simply: ovulation often occurs later in a longer cycle, and earlier in a shorter cycle. This may shift the estimated due date. Therefore, the ability to set the cycle length makes the result better suited to the body.
What if the result shows that I am "overdue"?
This doesn't necessarily mean anything bad. Some pregnancies last longer than 40 weeks. The doctor decides on the further course of action based on monitoring (e.g. CTG, ultrasound, assessment of the condition of the mother and child). The calculator only informs how the result compares to TP.
Can I calculate my gestational age for a specific date in the future?
Yes. TheReference Datefield is used for this purpose. Enter the date of your visit, examination or planned event, and the calculator will provide your pregnancy age and progress "as of that date." This is convenient when planning and talking to medical staff.
Is the "date of conception" in the report reliable?
This isan approximation of. Ovulation does not always occur exactly in the middle of the cycle, and the body may react to various factors. If you need precision, the reference point is ultrasound in early pregnancy.
Summary
Pregnancy and due date calculator is a simple tool that gives quick answers to the most common questions:when is the due date, what week of pregnancy is it, what trimester am I inand what dates are key in the calendar. Thanks to the option to set the cycle length, the result is better adjusted, and a clear report helps in planning the next weeks. Treat calculations as informative and organizing values - and in medical matters, always follow the doctor's/midwife's recommendations and test results.
Launch pregnancy calculator