iPhone or iPad: tap Download, open the file, then choose Add All to Calendar.
Computer or Android: download the file, then import it into Google Calendar under Settings, Import and export.
This is a snapshot of your dates. If your health professional records a different estimated due date, use the calculator below to create a new calendar.
Calculate your pregnancy dates
Choose the information you know. Dates are calculated as calendar days using the Australia/Sydney timezone.
Check the information entered
Your Pregnancy Calculation
Based on the information you entered.
Estimated due dateThe date the pregnancy is estimated to reach approximately 40 weeks.
Estimated gestational age
Current pregnancy week
Current trimester
Time remaining
Estimated conception dateThis is an approximation and does not identify the exact date conception occurred.
Calculation method
How was this result calculated?
Learn more about my current pregnancy week
Email your personalised pregnancy calendar
Receive your pregnancy weeks, trimester dates and estimated due date in a calendar you can add to Apple Calendar, Google Calendar or another compatible calendar.
Estimated due date
Current pregnancy stage
Next weekly milestone
Next major milestone
Want to download it now?
You do not have to wait for the email. This adds the calendar straight to your device.
Gestational age describes how far the pregnancy has progressed.
It is normally expressed as completed weeks and additional days since the last completed week.
Seven weeks and four days means that seven full weeks have been completed and another four days have passed.
The pregnancy is progressing through its eighth week, although the more precise gestational-age result remains seven weeks and four days.
Current pregnancy week
Completed gestational weeks and the pregnancy week currently in progress are related, but they are expressed differently.
Measurement
Example
Completed gestational age
7 weeks and 4 days
Current pregnancy week
Week 8
The calculator displays both values to make the result easier to understand.
Estimated conception date
The conception date shown by the calculator is an approximation derived from the pregnancy dates entered.
Pregnancy dating normally begins before conception. In a typical cycle, conception occurs approximately two weeks after the first day of the last period, although actual ovulation and conception timing can vary.
How Is a Pregnancy Due Date Calculated?
A pregnancy due date is commonly estimated by counting 280 calendar days from the first day of the last menstrual period.
The calculator can also work backwards from a known EDD to calculate gestational age today or on another selected date.
Calculating from your last menstrual period
The last menstrual period, commonly shortened to LMP, means the menstrual period immediately before the pregnancy.
Enter the first day bleeding started, not the day the period ended.
The calculator then:
Uses the first day of the LMP as the estimated gestational starting date.
Adds 280 calendar days to estimate the due date.
Counts from the LMP to today.
Converts the result into completed weeks and additional days.
This method is most useful when the date is known and menstrual cycles are regular.
Does the calculator adjust for cycle length?
No. The LMP mode uses the standard 280-day method and assumes a menstrual cycle close to 28 days.
A shorter cycle may be associated with earlier ovulation, while a longer cycle may be associated with later ovulation. This means the standard result may be less useful for people whose cycles are substantially shorter, longer or irregular.
Discuss your pregnancy dates with a health professional when you are unsure about the LMP or cycle pattern.
Calculating from a known estimated due date
When you enter a known EDD, the calculator counts back 280 days to establish the gestational starting point used for the calculation.
It then measures gestational age from that point to today or another date you select.
Use the due date documented by a health professional where possible.
Continue using the EDD in your clinical record even when an online calculator produces a different estimate.
Why is pregnancy counted before conception?
The exact date of conception is often unknown. Pregnancy dating therefore conventionally begins from the first day of the last menstrual period.
In a typical 28-day cycle, this includes approximately two weeks before conception.
How Many Weeks Pregnant Am I?
The calculator determines the number of calendar days between the estimated gestational starting date and today or another selected date.
It divides the total into completed seven-day weeks and additional days.
53 gestational days
= 7 completed weeks
+ 4 additional days
= 7 weeks and 4 days pregnant
A known due date can also be used to estimate how many weeks and days pregnant you will be on a future appointment or other selected date.
Do not use an online calculation to replace a due date documented by your health professional.
How Accurate Is a Due Date Calculator?
A due-date calculator provides an estimate. Its usefulness depends on the calculation method and the reliability of the information entered.
An LMP-based result is generally more useful when:
The first day of the last period is known.
The entered date is accurate.
Menstrual cycles are regular.
The cycle is close to 28 days.
It may be less reliable when:
Cycles are irregular.
The cycle is considerably shorter or longer than 28 days.
The LMP date is uncertain.
Contraception affected the menstrual cycle.
Ovulation occurred earlier or later than the standard calculation assumes.
Pregnancy, Birth and Baby notes that long or irregular cycles, an unknown LMP and conception while using cycle-affecting contraception are reasons a dating scan may be useful.
A health professional can help determine which due date should be used when menstrual and ultrasound estimates differ.
What If My Periods Are Irregular?
An LMP-based estimate may be less reliable when menstrual cycles are irregular because ovulation may not have occurred at the time assumed by the standard calculation.
You may still use the result as an approximate educational guide, but do not change the entered dates merely to produce the result you expected.
Speak with a health professional when:
You do not know the first day of your last period.
Your periods are irregular.
Your cycle is consistently shorter or longer than 28 days.
You recently stopped cycle-altering contraception.
The calculator differs from a professionally documented EDD.
You are unsure which pregnancy date should be used.
A dating scan may help estimate gestational age when menstrual dates are uncertain.
Calculating a Due Date With Irregular Periods
Can an Ultrasound Change Your Due Date?
An early ultrasound may confirm or produce a different estimated due date, particularly when the last menstrual period is uncertain or menstrual cycles are irregular.
A dating scan is an ultrasound used to estimate gestational age and an EDD. Pregnancy, Birth and Baby says dating scans are most often performed in the first trimester, usually between six and eight weeks.
This calculator does not:
Interpret ultrasound images.
Calculate gestational age from fetal measurements.
Decide whether a clinical EDD should change.
Replace a health professional.
Use the due date documented by a health professional.
LMP Due Date Versus Ultrasound Due Date
What Is Gestational Age?
Gestational age is the length of a pregnancy measured from the first day of the last menstrual period or an equivalent clinically established gestational starting date.
It is different from fetal or conceptional age.
Term
Meaning
Gestational age
Pregnancy age measured from the conventional obstetric starting point
Fetal or conceptional age
Approximate time since conception
Current pregnancy week
The week of pregnancy currently in progress
Estimated due date
The date at which the pregnancy reaches approximately 40 weeks
Because gestational age includes time before conception, it is commonly greater than the estimated time since conception.
Gestational Age Versus Fetal Age
What Trimester Am I In?
Pregnancy is commonly divided into three trimesters, but health resources do not all use identical transition weeks.
For consistency, this calculator uses:
Trimester
Gestational-age range
First trimester
0 weeks to 13 weeks and 6 days
Second trimester
14 weeks to 26 weeks and 6 days
Third trimester
From 27 weeks
These boundaries follow the trimester ranges published by Pregnancy, Birth and Baby, which places the start of the third trimester at 27 weeks.
Your health professional or another pregnancy resource may describe trimester transitions slightly differently. Gestational age in completed weeks and days is the more precise result.
Before the estimated due date, the calculator shows the approximate number of completed weeks and additional days remaining.
Approximately 32 weeks and 3 days remain until your estimated due date.
This is a calendar calculation. It does not predict when labour will begin.
On the EDD, the calculator displays: Your estimated due date is today.
After the EDD, it displays: Your estimated due date has passed. Continue following the care plan provided by your health professional, and contact them if you are unsure what to do next.
The calculator never displays a negative number of days remaining.
What Happens If the Estimated Due Date Has Passed?
An EDD is a reference point rather than a guaranteed date of birth.
When the dates produce a result from 42 weeks through 42 weeks and 6 days, the calculator displays the result with this notice:
The information entered produces an estimate of 42 weeks or more. Check the dates and contact a health professional for individual advice.
At 43 weeks or more, the calculator does not display a standard result. It asks the user to check the dates and seek professional advice.
The calculator cannot assess the pregnancy, monitor the baby or advise whether labour should be induced.
Frequently Asked Questions
Can this calculator confirm that I am pregnant?+
No. The calculator estimates pregnancy dates from the information entered. It cannot confirm pregnancy.
Use an appropriate pregnancy test and seek advice from a health professional where needed.
Can I calculate how many weeks pregnant I will be on a future date?+
Yes. Choose the known-due-date method, enter your EDD and select the future date you want to calculate.
The result will show your estimated gestational age in completed weeks and additional days on that date.
What should I enter if I do not know my last period?+
Use a due date documented by your health professional where one is available.
When neither the LMP nor a professionally supplied EDD is known, speak with a health professional about appropriate pregnancy dating.
Does the calculator adjust for menstrual-cycle length?+
No. The calculator uses the standard 280-day method and assumes a cycle close to 28 days.
If your cycle is shorter, longer or irregular, the calculated due date may be less reliable.
Why are completed weeks different from the current pregnancy week?+
Completed weeks count full seven-day periods.
At seven weeks and four days, seven full weeks have been completed and the pregnancy is progressing through week eight.
The calculator uses completed weeks and additional days as the primary gestational-age result.
Which due date should I use if my calculator and ultrasound dates differ?+
Use the EDD documented by a health professional.
An online calculator should not be used to override a clinical record.
Is the estimated conception date exact?+
No. It is an approximation derived from the pregnancy dates entered.
Ovulation, fertilisation and implantation do not always occur on a predictable calendar date.
Is a due date exactly 40 weeks?+
An EDD represents approximately 40 weeks under the calculation method used.
It does not mean labour or birth will occur on that exact date.
Can my estimated due date change?+
A health professional may confirm or revise the EDD when more reliable pregnancy-dating information becomes available.
Continue using the date they have recorded.
Is gestational age the same as fetal age?+
No. Gestational age is measured from the conventional pregnancy starting point. Fetal age is the approximate time since conception and is commonly about two weeks less in a typical cycle.
Follow Your Pregnancy Week by Week
Use your estimated due date to create a personalised pregnancy calendar and explore educational information for each stage of pregnancy.
Pregnancy weeks-to-months calculatorConvert gestational weeks into an approximate pregnancy month.
How pregnancy weeks are calculatedLearn how LMP, due dates and completed weeks are connected.
Gestational age versus fetal ageUnderstand the difference between pregnancy dating and time since conception.
LMP due date versus ultrasound due dateLearn why menstrual and ultrasound estimates may differ.
Due-date calculation with irregular periodsUnderstand the limitations of standard LMP dating.
Pregnancy week-by-week guideExplore each stage of pregnancy by gestational week.
Supporting Nutrition During Pregnancy
Nutritional needs can change during pregnancy. Read our medically reviewed pregnancy nutrition guide and speak with your health professional about what is appropriate for you.
