How to Calculate Pregnancy Weeks  and Due Date 

Hello Moms-to-be! If your first-time mom then, I am sure you might be confused about how to calculate pregnancy weeks, right. In this article, I am going to help you step by step how to understand weeks into Months and Trimesters.

A missed period is the first sign of pregnancy. If you don’t remember your last month’s period date then your doctor may use any of these methods to know your pregnancy. Pregnancy can be an estimate based on these 3 steps which will help you calculate the likely date of birth.

  • Last Menstrual Period Date
  • Using Ultrasound, Through Sonography
  • Physical Examination

Last Menstrual Period Date and period length are commonly used for confirming pregnancy and to calculate. Ultrasound works even when you are not aware of LMP  or if your periods are irregular and sonography helps measures the baby from head to toe. This gives the crown-rump length or CRL that is the length of human embryos. By physical examination, you can know your pregnancy week by the size of the uterus. These 3 helps your doctor to estimate pregnancy week based on the growth of your baby.

Given an example for you  –  if 1 December 2019 was your first day of last month period. You both involved in lovemaking in December and in the month of January you missed your period. And your pregnancy gets confirmed that you’re pregnant.

As per pregnancy rules, the First Day of the LMP date counts as Zero Week pregnant. 1 December 2019 is counted as first-week pregnancy as per you but you’re in your zero-week pregnancy.

So, here you’re in your zero weeks. As given below you will be one week pregnant during your second week. It’s all that you have to put one week behind you and start the count from another week.

  • In your first week you are – zero week’s pregnant
  • In your second week you are – one week pregnant
  • In your third week you are – two weeks pregnant
  • In your fourth week you are – three weeks pregnant
  • In your fifth week you are – four weeks pregnant, Here is where your pregnant gets confirmed.

So, you’re in First-month pregnancy which is called 1st Trimester. The given trimester’s chart is going to help you understand weeks into months.

You can find out your pregnancy weeks and estimated due date by using Your YouTube Mom pregnancy calculator accurately.

Pregnancy week by month chart to understand the 3 trimesters

Pregnancy week by month chart to understand the 3 trimesters of pregnancy  First Trimester Weeks (1st Trimester)

  • 01-04 weeks: First month of pregnancy (1 month)
  • 05-08 weeks: Second month of pregnancy (2 months)
  • 09-13 weeks: Third month of pregnancy (3 months)

Second Trimester Weeks (2nd Trimester)

  •  14-17 weeks: Fourth month of pregnancy (4 months)
  • 18-21 weeks: Fifth month of pregnancy (5 months)
  • 22-26 weeks: Sixth month of pregnancy (6 months)

 Third Trimester Weeks (3rd Trimester)

  • 27-30 weeks: Seventh month of pregnancy (7 months)
  • 31-35 weeks: Eighth month of pregnancy (8 months)
  • 36-40 weeks: Ninth month of pregnancy (9 months)


Disclaimer: This information is just a guide. Please note, your portion consumed will depend on your body weight, this meal plan is to ensure a balanced diet that helps you in healthy eating during pregnancy. The content work protected under copyright law. The background music is taken from the royalty-free site. Please contact us directly at [email protected]