What Trimester Am I?

Our trimester calculator calculates which trimester you are in now, based on how many weeks' pregnant you currently are.
Please Enter Your Weeks
   
*Calculate how many weeks if unknown.

About What Trimester Am I?

Trying to remember which trimester you are in and how many weeks are in each trimester can be difficult but the guesswork is eliminated with a calculator.

Each calculation will give you specific information about:

  • The trimester you are in
  • How many weeks to go in that trimester
  • When a new trimester will begin

What is a Trimester?

In general, a trimester refers to a period of three months or thereabouts.

What is a Pregnancy Trimester?

In pregnancy, there are three trimesters, each one defined by particular weeks of pregnancy. The following table shows the three trimesters and the weeks by which they are defined.[1]

Trimester One

Week 0 through
Week 13

1st Trimester is
14 weeks' Long

Trimester Two

Week 14 thorough
Week 26

2nd Trimester is
13 weeks' Long

Trimester Three

Week 27 through
Week 40

3rd Trimester is
14 weeks' Long


When does the first trimester start?
0 Weeks
When does the first trimester end?
12 Weeks and 6 Days
When does the second trimester start?
13 Weeks
When does the second trimester end?
26 Weeks and 6 Days
When does the third trimester start?
27 Weeks
When does the third trimester end?
40 Weeks and 6 Days

Please Note:

Weeks and days refer to gestational weeks and days (counted from the first day of the last menstrual period or start date calculated from ultrasound)

References

1. American College of Obstetricians and Gynecologists. FAQ Pregnancy. http://www.acog.org/Patients/FAQs/Prenatal-Development-How-Your-Baby-Grows-During-Pregnancy


Disclaimer: All information featured on weeksduringpregnancy.com should be used for educational purposes only and is not intended to replace medical advice.
Consult your doctor, physician or midwife regarding any personal pregnancy issues or medical conditions.