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Pregnancy Milestones Calculator

See the dates of key pregnancy milestones — second-trimester start, anatomy scan, viability, third trimester, full term and your due date — from your last period.

First day of your last period

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How it works

Each milestone date = first day of last period + (milestone week × 7 days). Weeks are gestational, counted from the last period.

Pregnancy milestones are tied to gestational week, so once the last-period date is fixed each one falls on a predictable calendar date. The second trimester begins at 14 weeks, the detailed anatomy scan is usually offered around 18–22 weeks, viability is a milestone near 24 weeks, and the third trimester begins at 28 weeks with full term at 39–40. Exact appointment timing and which screenings are offered depend on your provider and local guidelines.

Worked example

For a last period on June 1, 2026, the second trimester begins September 7, 2026 (14 weeks), the anatomy scan lands around October 19, the third trimester begins December 14, and the due date is March 8, 2027.

Frequently asked questions

When is the anatomy scan done?

Usually between about 18 and 22 weeks, most often around 20 weeks. This tool marks the 20-week point; your clinic schedules the exact appointment.

What does the “viability” milestone mean?

Around 24 weeks a baby born early has a meaningfully improved chance of survival with intensive care. It is a general population milestone, not a guarantee for any individual pregnancy.

Are these the exact dates my clinic will use?

They are estimates from your last period. If an ultrasound revised your dates, or your clinic uses slightly different windows, follow their schedule.

Related calculators

Due Date Calculator

Estimate your baby’s due date from your last period (with your cycle length), conception date, IVF transfer, an ultrasound or a known due date — with how far along you are, your trimester, a milestone timeline and a week-by-week calendar.

Trimester Calculator

Enter how many weeks pregnant you are and see your trimester, how far into it you are, and how long until the next one begins.

Pregnancy Week Calculator

Find out how many weeks and days pregnant you are — from your last period, due date, conception, IVF transfer or an ultrasound — with your pregnancy week, month, trimester, days remaining and a milestone timeline, today or on any date.

Gestational Age Calculator

Work out gestational age in weeks and days on any date — from your last period or from a dated ultrasound measurement.

Pregnancy Countdown Calculator

Count down the weeks and days left until your due date — with weeks to full term and how far along you are today.

Educational estimates from standard formulas and population averages — every pregnancy and baby is different. This is not medical advice; your doctor, midwife or pediatrician, with an examination or ultrasound, gives the accurate guidance.