Pregnancy Term Calculator

Due date & pregnancy timeline

See the whole journey at a glance

Calculate a conventional estimated due date, then explore a calm, visual week-by-week guide with clearly labelled milestones.

Estimated due date

Planning date

Example timeline

Oct 7, 202440 weeks from the conventional dating anchor

Pregnancy today: Loading…
Pregnancy progress: Loading…
Until estimated due date: Loading today’s date

ACOG full-term windowSep 30 – Oct 13, 2024

39+0 through 40+6 weeks

An estimated due date is a planning estimate. A clinician may revise it after ultrasound dating; this page does not handle IVF transfer or ultrasound redating.

Estimated 42-week guide

Milestones at a glance

Dates follow the estimated due date. The round-fruit trail runs from smallest to largest as an intuitive comparison with the typical baby size at each stage, not an individual clinical measurement.

First0+0 – 13+6

Second14+0 – 27+6

Third28+0 – 40+6

5weeks

Approximate baby-size comparisonsesame seedStage 1 of 12 · illustrative familiar-object scale

Feb 5, 2024

Early development

The brain and spinal cord are beginning to take shape. Development varies from pregnancy to pregnancy.

First trimester

7weeks

Approximate baby-size comparisonblueberryStage 2 of 12 · illustrative familiar-object scale

Feb 19, 2024

Early ultrasound window

Embryonic cardiac activity may be visible on an early ultrasound; timing and visibility vary.

First trimester

12weeks

Approximate baby-size comparisoncherryStage 3 of 12 · illustrative familiar-object scale

Mar 25, 2024

Dating scan window

A dating scan is commonly offered around 11 to 14 weeks and may revise the estimated due date.

First trimester

14weeks

Approximate baby-size comparisonapricotStage 4 of 12 · illustrative familiar-object scale

Apr 8, 2024

Second trimester begins

The second trimester begins at 14 weeks and 0 days under the ACOG trimester definition.

Second trimester

16weeks

Approximate baby-size comparisonplumStage 5 of 12 · illustrative familiar-object scale

Apr 22, 2024

Movement window approaches

Some people begin to notice movement in the following weeks; first movements can be felt later too.

Second trimester

20weeks

Approximate baby-size comparisonlimeStage 6 of 12 · illustrative familiar-object scale

May 20, 2024

Mid-pregnancy scan

The 20-week screening scan is commonly offered between 18 and 21 weeks.

Second trimester

24weeks

Approximate baby-size comparisonlemonStage 7 of 12 · illustrative familiar-object scale

Jun 17, 2024

Growth continues

This is a visual checkpoint only. Individual growth cannot be assessed from a calendar.

Second trimester

28weeks

Approximate baby-size comparisonmandarinStage 8 of 12 · illustrative familiar-object scale

Jul 15, 2024

Third trimester begins

The third trimester begins at 28 weeks and 0 days under the ACOG trimester definition.

Third trimester

33weeks

Approximate baby-size comparisonorangeStage 9 of 12 · illustrative familiar-object scale

Aug 19, 2024

Growth and maturation

Growth and maturation continue. A calendar cannot predict fetal position, size, or readiness for birth.

Third trimester

37weeks

Approximate baby-size comparisongrapefruitStage 10 of 12 · illustrative familiar-object scale

Sep 16, 2024

Early term begins

ACOG defines early term as 37 weeks and 0 days through 38 weeks and 6 days.

Third trimester

39weeks

Approximate baby-size comparisoncantaloupeStage 11 of 12 · illustrative familiar-object scale

Sep 30, 2024

Full term begins

ACOG defines full term as 39 weeks and 0 days through 40 weeks and 6 days.

Third trimester

40weeks

Approximate baby-size comparisonwatermelonStage 12 of 12 · illustrative familiar-object scale

Oct 7, 2024

Estimated due date

The estimated due date is a planning estimate, not a deadline or a prediction of the actual birth date.

Third trimester

View all 42 weekly date rangesWeek 40 starts on the estimated due date

Dating startsJan 1, 20240 weeks + 0 days

Week 1Jan 8 – Jan 14, 20241+0 – 1+6

Week 2Jan 15 – Jan 21, 20242+0 – 2+6

Week 3Jan 22 – Jan 28, 20243+0 – 3+6

Week 4Jan 29 – Feb 4, 20244+0 – 4+6

Week 5Feb 5 – Feb 11, 20245+0 – 5+6

Week 6Feb 12 – Feb 18, 20246+0 – 6+6

Week 7Feb 19 – Feb 25, 20247+0 – 7+6

Week 8Feb 26 – Mar 3, 20248+0 – 8+6

Week 9Mar 4 – Mar 10, 20249+0 – 9+6

Week 10Mar 11 – Mar 17, 202410+0 – 10+6

Week 11Mar 18 – Mar 24, 202411+0 – 11+6

Week 12Mar 25 – Mar 31, 202412+0 – 12+6

Week 13Apr 1 – Apr 7, 202413+0 – 13+6

Week 14Apr 8 – Apr 14, 202414+0 – 14+6

Week 15Apr 15 – Apr 21, 202415+0 – 15+6

Week 16Apr 22 – Apr 28, 202416+0 – 16+6

Week 17Apr 29 – May 5, 202417+0 – 17+6

Week 18May 6 – May 12, 202418+0 – 18+6

Week 19May 13 – May 19, 202419+0 – 19+6

Week 20May 20 – May 26, 202420+0 – 20+6

Week 21May 27 – Jun 2, 202421+0 – 21+6

Week 22Jun 3 – Jun 9, 202422+0 – 22+6

Week 23Jun 10 – Jun 16, 202423+0 – 23+6

Week 24Jun 17 – Jun 23, 202424+0 – 24+6

Week 25Jun 24 – Jun 30, 202425+0 – 25+6

Week 26Jul 1 – Jul 7, 202426+0 – 26+6

Week 27Jul 8 – Jul 14, 202427+0 – 27+6

Week 28Jul 15 – Jul 21, 202428+0 – 28+6

Week 29Jul 22 – Jul 28, 202429+0 – 29+6

Week 30Jul 29 – Aug 4, 202430+0 – 30+6

Week 31Aug 5 – Aug 11, 202431+0 – 31+6

Week 32Aug 12 – Aug 18, 202432+0 – 32+6

Week 33Aug 19 – Aug 25, 202433+0 – 33+6

Week 34Aug 26 – Sep 1, 202434+0 – 34+6

Week 35Sep 2 – Sep 8, 202435+0 – 35+6

Week 36Sep 9 – Sep 15, 202436+0 – 36+6

Week 37Sep 16 – Sep 22, 202437+0 – 37+6

Week 38Sep 23 – Sep 29, 202438+0 – 38+6

Week 39Sep 30 – Oct 6, 202439+0 – 39+6

Week 40Oct 7 – Oct 13, 202440+0 – 40+6

Week 41Oct 14 – Oct 20, 202441+0 – 41+6

Week 42Oct 21 – Oct 27, 202442+0 – 42+6

Formula and review status

Adds the conventional 280 days to the first day of an LMP or 266 days to a genuinely known conception/fertilization date. It does not replace ultrasound dating or handle embryo-transfer dating.

Formula: health.pregnancy-due-date.v1
Version: 1.0.0
Execution: release

Pregnancy term and estimated due date

Pregnancy is usually dated from the first day of the last menstrual period, even though fertilization generally occurs later. That convention places an average pregnancy at 280 days, or 40 weeks. If the fertilization date is genuinely known, this calculator adds 266 days and still expresses progress on the same gestational-age timeline.

The result is an estimated due date, not a prediction of the exact day of birth. It gives you one consistent planning point for today's gestational age, trimester, days remaining, weekly date ranges, and milestone guide. A clinician may confirm or revise dating using the pregnancy history and an ultrasound.

How pregnancy dating works

estimated due date = first day of LMP + 280 days · estimated due date = known fertilization date + 266 days

Dating relationship

Two known-date paths meet the same estimated due date

First day of LMPGestational day 0+ 280 days

Known fertilizationGestational day 14+ 266 days

Shared endpointEstimated due date

First trimester0w–13w 6d
Second trimester14w–27w 6d
Third trimester28w–40w

A known fertilization date is placed at about two gestational weeks, which is why adding 266 days reaches the same 40-week endpoint as adding 280 days to the first day of the LMP.

Choose the date basis you actually know. Do not enter a date of intercourse as a known fertilization date, because conception cannot be pinpointed from intercourse alone. IVF embryo-transfer dating and ultrasound redating use different rules; use the dedicated IVF Due Date Calculator or your clinician's established date instead.

Understanding today's pregnancy progress

After you calculate, the result shows today as completed gestational weeks plus additional days, the total gestational day, and the number of calendar days until the estimated due date. The milestone closest to the current stage is highlighted automatically. These values advance by calendar date; they do not measure fetal growth or confirm that a pregnancy is developing as expected.

The three trimester bands follow the common clinical convention: first trimester through 13 weeks and 6 days, second trimester from 14 weeks through 27 weeks and 6 days, and third trimester from 28 weeks onward. The fruit trail turns the typical size at each stage into a familiar, easy-to-picture comparison. It is an approximate teaching aid rather than a biometric measurement of an individual baby.

Pregnancy testing and prenatal care

A calendar cannot confirm pregnancy. If a period is late or pregnancy is possible, use an appropriate pregnancy test and contact a qualified health professional about the result and next steps. Prenatal care can include medical history, medication and supplement review, screening, measurements, and individualized timing for visits or ultrasound.

Medication, movement, and nutrition

Do not start, stop, or change prescription medicine because of a calculator result. Review prescription drugs, over-the-counter products, vitamins, and supplements with a qualified clinician. Nutrition, exercise, weight goals, and activity limits during pregnancy depend on personal health and pregnancy factors; general fitness targets are not a substitute for prenatal guidance.

For an uncomplicated pregnancy, regular activity may be appropriate, but symptoms, medical conditions, and pregnancy complications can change what is safe. Seek individualized advice and urgent assessment for concerning symptoms rather than relying on a date or milestone card.

Related pregnancy and cycle calculators

Ovulation Date Calculator: Estimate a calendar ovulation date from a declared cycle pattern for planning only.
Conception Date Calculator: Compare conception-date estimates, broad windows, and a linked due date without claiming an exact conception event.
Menstrual Cycle Calculator: Build a calendar from entered cycle dates before using an LMP-based pregnancy estimate.
IVF Due Date Calculator: Use embryo-transfer inputs and the ART-specific date convention that this page intentionally does not infer.
BMI Calculator: Review a prepregnancy adult BMI separately; BMI during pregnancy should not be interpreted with ordinary adult weight categories.

Questions and answers

Why does pregnancy dating start before conception?: Gestational age traditionally starts on the first day of the LMP. That makes a genuinely known fertilization date approximately 2 weeks and 0 days on the same clinical timeline.
Will birth happen on the estimated due date?: The due date is a reference point for planning and clinical timing, not a promise of the birth date. Labor may occur before or after it.
What does the fruit comparison say about baby size?: It gives an intuitive approximation of the typical scale at that stage by comparing it with a familiar fruit. It cannot measure an individual baby or evaluate growth; that requires appropriate clinical assessment.
What if my ultrasound gives a different date?: Use the date established by your qualified prenatal-care professional. This calculator does not decide whether or when an ultrasound should replace an LMP date.

Sources and important limitations

Dating and trimester language is based on guidance from the American College of Obstetricians and Gynecologists; its fetal-growth overview supplies the gestational-age, trimester, and clinical measurement context. The NHS week-by-week pregnancy guide supplies published week-specific growth and familiar-object context for the baby-size teaching comparison. This page keeps an all-fruit trail as an intuitive editorial scale; the icons are not drawn to clinical scale and cannot measure an individual baby. Prenatal-care context is summarized from the ACOG prenatal-care FAQ. This page cannot confirm pregnancy, assess viability or growth, diagnose symptoms, choose medication, determine paternity, or replace prenatal care.

Important limitations

The result is a calendar estimate, not confirmation of pregnancy, fetal growth, viability, the actual birth date, or individualized medical advice. Clinician-established ultrasound dating and prenatal care take priority.

This formula passed its registered engineering tests and is published under an explicit site-owner policy authorization. No independent expert, QA, editorial, legal, or third-party review is claimed. Verify consequential results with a qualified professional.

This subject may affect health, finance, tax, legal, or other consequential decisions. It has not received an independent domain-expert review; consult a qualified professional before relying on it.

Choose the date you know

Planning date

Early development

Early ultrasound window

Dating scan window

Second trimester begins

Movement window approaches

Mid-pregnancy scan

Growth continues

Third trimester begins

Growth and maturation

Early term begins

Full term begins

Estimated due date

Pregnancy term and estimated due date

How pregnancy dating works

Understanding today's pregnancy progress

Pregnancy testing and prenatal care

Medication, movement, and nutrition

Related pregnancy and cycle calculators

Questions and answers

Sources and important limitations

Important limitations

Choose the date you know

Planning date

Early development

Early ultrasound window

Dating scan window

Second trimester begins

Movement window approaches

Mid-pregnancy scan

Growth continues

Third trimester begins

Growth and maturation

Early term begins

Full term begins

Estimated due date

Pregnancy term and estimated due date

How pregnancy dating works

Understanding today's pregnancy progress

Pregnancy testing and prenatal care

Medication, movement, and nutrition

Related pregnancy and cycle calculators

Questions and answers

Sources and important limitations