Estimate your trimester changes, anatomy scan window, full-term dates, and hospital bag ready-by date from your due date, gestational age, or last menstrual period.
Enter the due date given by your healthcare provider.
This calculator takes your due date, gestational age, or LMP and uses the standard 280-day pregnancy model (40 weeks from LMP) to estimate each milestone date. All dates are estimates. Ultrasound dating from your provider is more accurate.
First trimester is week 1 through week 13 day 6. The second trimester typically begins at 14 weeks 0 days, and the third trimester begins at 28 weeks 0 days. These are standard clinical definitions though your provider may use slightly different cutoffs.
The anatomy scan (also called the 20-week scan or mid-pregnancy ultrasound) is typically scheduled between 18 and 22 weeks of pregnancy. It checks the baby's development, organs, and position of the placenta. Your provider will schedule this based on your specific situation.
Full term is defined as 39 weeks 0 days through 40 weeks 6 days. Babies born in this window are considered full term. Early term is 37–38 weeks, late term is 41 weeks, and post-term is 42 weeks or beyond. The American College of Obstetricians and Gynecologists (ACOG) defines these windows.
The "go bag ready" date at 37 weeks is a planning suggestion only — not a medical milestone. It's a popular guideline suggesting that by 37 weeks (the start of early term), you have your hospital bag packed and ready. Labor timing is unpredictable, so earlier preparation is better.
Most pregnancies involve several ultrasound scans at different stages. Each scan has a different purpose, and not all scans are routine for every pregnancy. Your provider will advise which scans are recommended based on your individual care plan. The windows below reflect typical scheduling — actual timing may vary.
| Scan | Typical Window | Purpose |
|---|---|---|
| Viability / Dating Scan | 6 – 10 weeks | Confirms heartbeat, checks for multiples, and establishes gestational age. Often the first scan. |
| Nuchal Translucency (NT) Scan | 11 – 14 weeks | Measures fluid at the back of the baby's neck to screen for chromosomal conditions. Usually combined with blood tests. |
| Anatomy Scan (Mid-Pregnancy) | 18 – 22 weeks | Detailed review of fetal anatomy, organ development, placenta position, and amniotic fluid. The most comprehensive routine scan. |
| Growth Scan | 28 – 32 weeks | Monitors fetal growth, weight estimates, and fluid levels in the third trimester. May be repeated if concerns arise. |
| Pre-Birth / Late Pregnancy Scan | 36 – 38 weeks | Checks baby's position (head-down vs. breech), placenta location, and fluid levels before birth. Not always routine. |
Scan schedules vary by country, healthcare system, and individual risk factors. Always follow your clinician's recommendations for your specific pregnancy.
The Pregnancy Milestone Calculator helps expecting parents estimate key pregnancy dates using one of three common starting points: an estimated due date, a current gestational age, or the first day of the last menstrual period (LMP). Once you enter your information, the tool maps your pregnancy against the standard 40-week / 280-day clinical model and returns a clear timeline of important milestones. This makes it easier to understand where you are now, what comes next, and how the rest of the pregnancy journey may unfold.
You can use the calculator in three different ways depending on what information you already have. If you know your due date, the tool works backward from that date to estimate milestone timing. If you know how many weeks and days pregnant you are today, it estimates your due date first and then calculates the rest of your timeline. If you know your LMP, it adds 280 days to estimate your due date and uses that to generate the milestone schedule. These three input modes make the calculator flexible for newly pregnant users, people already under prenatal care, and anyone comparing dating methods.
The calculator estimates seven key milestones: the date the first trimester ends, the start of the second trimester, the typical anatomy scan window, the start of the third trimester, a suggested hospital bag ready-by date, the full term window, and the estimated due date itself. Each milestone matters for a different reason. Trimester transitions help people understand symptom changes and planning stages. The anatomy scan is typically done between 18 and 22 weeks and is a major mid-pregnancy checkpoint. The full term window, defined as 39 weeks 0 days through 40 weeks 6 days, provides important context for birth timing. The "go bag" date is not a medical milestone, but it is a helpful planning reminder as labor can be unpredictable.
This tool is designed for expecting parents who want a simple, educational overview of their pregnancy timeline. It is useful for personal planning, appointment awareness, and understanding standard milestone definitions. However, all results are estimates only. Ultrasound dating, prenatal care decisions, and testing schedules may vary based on your medical history and your clinician's guidance. This calculator is for educational purposes only and should not be used as medical advice or as a substitute for professional prenatal care.
1. Choose your input mode: enter either your due date, your current gestational age, or the first day of your last menstrual period.
2. Enter the required information for the selected mode. Depending on your choice, that may be a calendar date or a weeks-and-days pregnancy count.
3. Hit Calculate to estimate your pregnancy timeline using the standard 280-day pregnancy model, which measures 40 weeks from LMP.
4. Review your milestone results, including estimated calendar dates and status badges that show whether each event is Passed, This Week, or Upcoming.
5. Use the visual timeline to see where you are in pregnancy overall, including trimester placement, the anatomy scan window, and the full-term range.
This calculator uses a standard obstetric dating model based on a 280-day pregnancy. If you enter a due date, all milestone dates are calculated backward or forward from the estimated due date (EDD = 40w0d). If you enter gestational age, the calculator first estimates the due date with the formula: EDD = today + (280 − gestationalAgeDays) days. If you enter LMP, it estimates the due date using: EDD = LMP + 280 days. Once the EDD is known, every milestone is derived from that anchor date.
The seven milestone formulas are:
First trimester end = EDD − 26 weeks 1 day
Second trimester start = EDD − 26 weeks
Anatomy scan window = EDD − 22 weeks through EDD − 18 weeks
Third trimester start = EDD − 12 weeks
Go bag ready by = EDD − 3 weeks
Full term window = EDD − 1 week through EDD + 6 days
Due date = EDD
The calculator also assigns a milestone status of Passed, This Week, or Upcoming based on today's date. Single-date milestones are marked as "This Week" when they fall within roughly seven days of the current date. Range-based milestones, such as the anatomy scan window and full-term window, are marked as "This Week" when today falls inside the range.
Assume a user enters LMP = January 1, 2025.
Step 1: Estimate the due date.
Using the standard 280-day model, EDD = October 8, 2025.
Step 2: Calculate each milestone from the EDD.
- First trimester end: April 8, 2025 (13w6d)
- Second trimester start: April 9, 2025 (14w0d)
- Anatomy scan window: May 7, 2025 – June 4, 2025 (18w–22w)
- Third trimester start: July 16, 2025 (28w0d)
- Go bag ready by: September 17, 2025 (37w0d)
- Full term window: October 1, 2025 – October 14, 2025 (39w–40w6d)
- Estimated due date: October 8, 2025
This example shows how one starting date can be used to estimate the full pregnancy timeline. In real life, your provider may confirm or adjust dating with ultrasound findings and clinical judgment.