Free Pregnancy Due Date Calculator Online - No Signup

Calculate an estimated due date, gestational age, trimester, conception timing, and important pregnancy milestones using your last period, conception date, IVF transfer, or an existing due date.

Calculate Due Date How dating works
Four calculation methods Gestational age Trimester timeline Calendar export

Pregnancy Due Date Calculator

Choose the dating information you have. Results are calendar estimates and do not replace clinical dating, ultrasound, or professional care.

Runs privately in your browser
Choose a calculation method

Enter the first day of menstrual bleeding, not the day the period ended.

The due date is adjusted when your average differs from 28 days.

Use a known or estimated conception date. Actual conception timing may be uncertain.

Enter the date the embryo transfer was performed.

IVF dating accounts for embryo age on the transfer date.

Use a due date previously provided by a qualified healthcare professional.

Pregnancy dating is approximate. A clinician may revise an estimated due date after reviewing history or ultrasound measurements.

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Four dating methods LMP, conception, IVF, or EDD
02
Private calculation Dates stay in your browser
03
Milestone timeline Trimester and term estimates
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Calendar export Download an ICS timeline
Understanding due-date estimates

How pregnancy due dates and gestational age are estimated

Pregnancy due dates are commonly expressed as 40 weeks from the first day of the last menstrual period. This equals approximately 280 days, even though conception usually occurs about two weeks after the start of the last period in a standard calendar model.

If conception timing is known, an estimated due date can be calculated by adding approximately 266 days. IVF dating can use the transfer date and embryo age because those details are more specifically documented.

A due date remains an estimate. Pregnancy length varies, and a healthcare professional may use menstrual history, assisted-reproduction records, ultrasound measurements, and clinical judgment when establishing or revising an official estimated due date.

Why an ultrasound date may differ

Last-period dating assumes that the date is remembered accurately and that cycle timing follows a predictable pattern. Early ultrasound measurements may provide additional information when dates are uncertain or cycles are irregular.

Three simple steps

How to calculate an estimated pregnancy due date

Select the information you know, calculate the timeline, and review the result as an estimate rather than a diagnosis.

Step 1

Choose a dating method

Use your last period, conception date, IVF transfer, or an existing estimated due date.

Step 2

Enter the relevant date

Provide the requested date and, where relevant, average cycle length or embryo age.

Step 3

Review your timeline

View gestational age, trimester, conception estimate, and calendar-based pregnancy milestones.

Calculation methods

Different ways to estimate a pregnancy due date

Each method begins with different information but converts it into a common estimated 40-week gestational timeline.

Method 1

Last menstrual period

The common LMP method adds 280 days to the first day of the last period. This calculator also adjusts the result when an average cycle length other than 28 days is entered.

Method 2

Conception date

A conception-based estimate adds 266 days to the known or estimated conception date. Natural conception timing is often uncertain.

Method 3

IVF embryo transfer

A day-3 transfer estimate adds 263 days to the transfer date. A day-5 embryo or blastocyst transfer estimate adds 261 days.

Method 4

Existing estimated due date

If an estimated due date is already available, the calculator can work backward to estimate current gestational age and milestone dates.

Timeline capabilities

More than a single date on the calendar

Explore a complete educational pregnancy timeline with responsive results and practical export options.

Estimated due date

Calculate a central estimated due date from the dating information available to you.

Gestational age

See the estimated pregnancy age in completed weeks and additional days.

Trimester progress

Review your estimated position across the first, second, and third trimesters.

Private processing

Dates are processed locally by your browser without requiring an account or server-side calculation.

Calendar export

Download estimated trimester and term milestones as an ICS calendar file.

Copy or print

Save a plain-text summary or print a clean version of the estimated pregnancy timeline.

Responsible use

How to use due-date estimates appropriately

Treat online calculations as educational planning tools and rely on qualified care for pregnancy confirmation and dating.

1

Use the most reliable date available

IVF records or a clearly remembered menstrual date may provide different levels of certainty than an estimated conception date.

2

Remember that a due date is not a deadline

The estimated date is the center of a broader delivery window, not a guaranteed birth date.

3

Use the clinician-provided date for care

If your healthcare professional establishes or revises an estimated due date, use that date for medical planning.

4

Do not use the calculator for diagnosis

Dates alone cannot confirm pregnancy health, viability, fetal growth, or whether urgent care is needed.

When to seek qualified medical care

Contact a qualified healthcare professional for pregnancy confirmation, prenatal care, medication questions, symptom assessment, and individualized dating. Seek urgent care for severe abdominal or pelvic pain, heavy bleeding, fainting, breathing difficulty, seizures, or other severe symptoms.

Common questions

Pregnancy due date calculator FAQ

How is a pregnancy due date calculated from the last menstrual period?

A common estimate adds 280 days, or 40 weeks, to the first day of the last menstrual period. This assumes a typical cycle and remains an estimate.

How is a due date calculated from conception?

A conception-based estimate adds 266 days, or 38 weeks, to the estimated conception date.

How is an IVF due date calculated?

For IVF, a common calendar estimate adds 263 days to a day-3 embryo transfer date or 261 days to a day-5 embryo transfer date.

How accurate is a pregnancy due date calculator?

A due date is an estimate rather than a guaranteed delivery date. Clinical dating may change after ultrasound measurements or review by a qualified healthcare professional.

What is gestational age?

Gestational age is conventionally counted from the first day of the last menstrual period, approximately two weeks before conception in a standard calendar model.

Can this calculator confirm pregnancy?

No. A due date calculation cannot confirm pregnancy, viability, fetal development, or a medical condition.

Are the pregnancy dates I enter uploaded or stored?

No. The calculation runs locally in the browser and does not require the entered dates to be uploaded.

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Ready to estimate your pregnancy timeline?

Choose the dating information available to you and view an estimated due date, gestational age, trimester, and pregnancy milestones privately in your browser.

Calculate Due Date