Pregnancy Calculator

See your current pregnancy week and trimester, plus your estimated due date — based on your last menstrual period.

How to Use This Calculator

Enter the first day of your last period. If you know your conception date instead, use the Due Date Calculator. Key milestones along a 40-week pregnancy:

Weeks 1-13 — first trimester; morning sickness is common.
Weeks 14-27 — second trimester; many people feel most energetic here.
Weeks 28-40 — third trimester; baby grows rapidly.

Frequently Asked Questions

How is my due date calculated?

Standard practice is LMP plus 280 days (40 weeks). Only about 4% of babies arrive exactly on their due date.

Why is pregnancy counted from my period?

Historically the LMP is easier to date than conception. That's why week 1 and 2 occur before ovulation.

Is this calculator medical advice?

No — it is a planning estimate. Always follow your healthcare provider's dating from your ultrasound.

What if my cycle isn't 28 days?

The 280-day rule assumes a 28-day cycle. Your doctor will adjust using ultrasound if your cycle differs.

Practical Example

If your last period began on June 10:

Conception estimate ≈ June 24
Due date ≈ June 10 + 280 days = March 17
First trimester ends ≈ September 16

What Your Results Mean

Due date — an estimate, not a guarantee; only ~4% of babies arrive on the exact day.
Trimester dates — milestones that help you plan appointments.
Ultrasound dating from your provider is the most reliable reference.