how many week pregnant am i calculator

If you're asking, "How many weeks pregnant am I?", you're in the right place. Use this quick pregnancy week calculator to estimate your current gestational age, trimester, due date, and conception window.

How this pregnancy week calculator works

This pregnancy calculator uses standard obstetric dating rules used in many clinics:

• Gestational age is counted from the first day of your last menstrual period (LMP), not from conception day.
• Estimated due date is usually set at 40 weeks (280 days) from LMP.
• If your cycle is longer or shorter than 28 days, the estimate can be adjusted.

Method 1: Calculate from LMP

This is the most common approach. Enter the first day of your last period and your average cycle length. The calculator estimates how far along you are today in weeks + days.

Method 2: Calculate from due date

If you already have a due date from your provider or an ultrasound report, select the due date option. The calculator then works backward to estimate your current pregnancy week.

Understanding your results

Your result includes several useful numbers:

• Weeks pregnant: e.g., 19 weeks 3 days.
• Trimester: first, second, or third trimester.
• Estimated due date: projected date for 40 weeks.
• Estimated conception date: usually around 2 weeks after LMP in a 28-day cycle.
• Pregnancy progress: percent of 40 weeks completed.

Pregnancy timeline by trimester

First trimester (0 to 13 weeks, 6 days)

• Missed period and positive pregnancy test often happen here.
• Common symptoms include fatigue, nausea, breast tenderness, and frequent urination.
• Initial prenatal appointments and labs are usually scheduled in this stage.

Second trimester (14 to 27 weeks, 6 days)

• Many people notice improved energy and less nausea.
• Fetal anatomy ultrasound often occurs around 18 to 22 weeks.
• You may begin feeling regular fetal movement.

Third trimester (28 weeks to birth)

• Growth accelerates and prenatal visits become more frequent.
• You may notice Braxton Hicks contractions, reflux, or sleep changes.
• Labor can be considered full term between 39 and 40 weeks.

How accurate is a due date calculator?

A due date calculator gives a strong estimate, but only a small percentage of babies are born exactly on their due date. Actual delivery commonly occurs within a window around the due date.

Early ultrasound is often the best method to confirm or refine gestational age, especially if cycles are irregular or LMP is uncertain.

Frequently asked questions

What if my periods are irregular?

Use your best LMP estimate and cycle length, but expect less precision. Your prenatal provider may rely more on ultrasound dating.

Can conception date differ from ovulation date?

Yes. Conception typically occurs near ovulation, but sperm can survive for several days, so exact timing can vary.

Should I trust app dates or ultrasound dates?

For clinical care, your provider's dating (often based on early ultrasound) should be treated as the primary timeline.

Important note

This tool is for educational use only. If you have bleeding, pain, concerning symptoms, or questions about fetal growth, contact your OB-GYN, midwife, or healthcare professional promptly.