Pregnancy How Far Along Calculator
Use your last menstrual period, conception date, or due date to estimate how many weeks pregnant you are.
Most pregnancy dating starts from this date, not ovulation day.
Optional refinement for LMP method. Standard is 28 days.
This tool gives estimates for planning and education and does not replace medical advice.
What this calculator tells you
A how far along calculator estimates your gestational age: how many weeks and days pregnant you are right now. It also estimates your due date and where you are in each trimester.
- Weeks + days pregnant (example: 18 weeks, 3 days)
- Estimated due date based on your selected method
- Estimated conception date and LMP equivalent
- Trimester status and simple milestone dates
How to use the calculator
1) Last menstrual period (LMP)
This is the most common approach. Enter the first day of your last period. Pregnancy is traditionally counted from this date, even though conception usually occurs about two weeks later.
2) Conception date
If you know conception timing (for example, through ovulation tracking or fertility treatment), choose conception date. The calculator adds 14 days to estimate gestational age on the standard pregnancy timeline.
3) Due date
If your provider already gave you an estimated due date, choose due date. The calculator subtracts 280 days (40 weeks) to estimate LMP and current gestational age.
How pregnancy dating works
Most due date calculators use Naegele’s-style dating:
- EDD = LMP + 280 days (for a typical 28-day cycle)
- If cycles are longer or shorter, the estimate can shift by several days
- Early ultrasound often provides the most accurate dating if dates are uncertain
Because ovulation timing varies, this result should be treated as a best estimate, not an exact biological timestamp.
Milestones by week (quick reference)
- Week 6–8: Early prenatal visit is often scheduled
- Week 10–13: Common window for first-trimester screening discussions
- Week 18–22: Anatomy ultrasound is often performed
- Week 24–28: Typical glucose screening window
- Week 36+: Weekly visits often begin
- Week 40: Estimated due date (many babies arrive before or after)
Why your due date can change
It is common for the estimated due date to be adjusted, especially early in care. Reasons include:
- Irregular cycles or uncertain LMP
- Late ovulation compared with a textbook cycle
- Dating updates after first-trimester ultrasound
- Differences between app-based estimates and clinical dating methods
Frequently asked questions
Is “weeks pregnant” counted from conception?
Usually no. Standard obstetric dating starts from LMP, which is typically about two weeks before conception.
Can this tool tell me my exact delivery day?
No. It estimates a due date. Full-term delivery can naturally occur before or after that date.
What if I am using IVF dates?
Use the conception method as a rough estimate, then follow the timing provided by your fertility team for official dating.
Important note
This pregnancy week calculator is for educational use only. If you have bleeding, pain, severe nausea, reduced fetal movement, or any urgent concern, contact your clinician right away. For accurate medical dating and prenatal care decisions, always follow your OB-GYN or midwife.