How Many Weeks Pregnant Am I?

Estimate your pregnancy week from a due date, last menstrual period, or conception date. MiniWebtool’s How Many Weeks Pregnant Am I? shows weeks, trimester progress, and developmental milestones; clinical dating may differ from the estimate.

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About How Many Weeks Pregnant Am I?

Welcome to our Pregnancy Week Calculator, a comprehensive tool designed to help expecting mothers track their pregnancy journey. Whether you know your due date, last menstrual period (LMP), or conception date, this calculator instantly shows you how many weeks pregnant you are, along with trimester progress, baby size comparisons, and important developmental milestones.

At a Glance

How Many Weeks Pregnant Am I? estimates your current pregnancy week from a due date, last menstrual period or conception date. It also shows trimester progress, days remaining and baby size comparisons. Clinical dating may differ.

How Many Weeks Pregnant Am I?: features at a glance
Feature	What you get	Good for
Three start dates	Calculate from a due date (280 days back to LMP), the first day of your last period, or a conception date (2 weeks added).	Different dating situations, including IVF
Weeks and days left	Shows your current week of the standard 40-week (280-day) pregnancy, the progress percentage and days remaining.	Tracking how far along you are
Trimesters	A timeline marks trimester progress: weeks 1-12, 13-26 and 27-40.	Seeing which stage you are in
Baby size	Compares baby size with fruit, such as a raspberry at week 8 and a watermelon at week 40.	Sharing progress in a fun way
Milestones	Week-by-week development milestones, such as heartbeat on ultrasound at week 6 and the anatomy scan at weeks 18-20.	Knowing what is happening at each stage

How Pregnancy Weeks Are Calculated

Pregnancy is typically calculated from the first day of your last menstrual period (LMP), not from conception. This is the standard method used by healthcare providers worldwide. A full-term pregnancy is considered 40 weeks (280 days) from the LMP, even though actual conception typically occurs about 2 weeks after the LMP.

Calculation Methods Explained

From Due Date: If your doctor has given you a due date, we calculate backwards 280 days to determine your LMP, then calculate your current week from there.
From Last Menstrual Period (LMP): The traditional method - we count the days from the first day of your last period to today and convert to weeks.
From Conception Date: If you know when conception occurred (such as with IVF), we add 2 weeks to account for the difference between gestational age and fetal age.

Understanding the Three Trimesters

How Many Weeks Pregnant Am I?: Understanding the Three Trimesters
Trimester	Weeks	Key Developments	What to Expect
First	Weeks 1-12	Organ formation, heartbeat begins, neural tube develops	Morning sickness, fatigue, breast tenderness
Second	Weeks 13-26	Baby movement felt, gender can be determined, rapid growth	Increased energy, baby bump visible, fewer symptoms
Third	Weeks 27-40	Lungs mature, brain develops rapidly, weight gain	Back pain, frequent urination, nesting instinct

Baby Size Week by Week

One of the most exciting aspects of pregnancy is watching your baby grow! Here are common size comparisons used throughout pregnancy:

Popular Baby Size Comparisons

Week 4: Poppy seed (about 1mm)
Week 8: Raspberry (about 1.6cm)
Week 12: Lime (about 5.4cm)
Week 16: Avocado (about 11.6cm)
Week 20: Banana (about 16.5cm)
Week 24: Corn on the cob (about 30cm)
Week 28: Eggplant (about 37.6cm)
Week 32: Squash (about 42.4cm)
Week 36: Honeydew melon (about 47.4cm)
Week 40: Watermelon (about 51.2cm)

Important Pregnancy Milestones

First Trimester Milestones (Weeks 1-12)

Week 4: Implantation occurs, positive pregnancy test possible
Week 6: Heartbeat can be detected on ultrasound
Week 8: All major organs have begun forming
Week 10: Baby officially called a fetus (no longer embryo)
Week 12: Risk of miscarriage drops significantly

Second Trimester Milestones (Weeks 13-26)

Week 16: Baby can hear your voice
Week 18-20: Anatomy scan ultrasound, gender can be determined
Week 20: Halfway point! You may feel first movements (quickening)
Week 24: Viability milestone - baby has a chance of survival if born early

Third Trimester Milestones (Weeks 27-40)

Week 28: Eyes can open and close
Week 32: Baby practices breathing movements
Week 36: Baby is considered "early term"
Week 37: Baby is considered "full term"
Week 39-40: Optimal time for delivery

Frequently Asked Questions

How do I calculate how many weeks pregnant I am?

Pregnancy is calculated from the first day of your last menstrual period (LMP), not from conception. A typical pregnancy is 40 weeks (280 days) from LMP. To calculate your weeks pregnant: subtract your LMP date from today's date, then divide by 7. Alternatively, if you know your due date, subtract 280 days to find your LMP, then calculate from there.

What are the three trimesters of pregnancy?

Pregnancy is divided into three trimesters: First trimester (weeks 1-12) involves major organ development and highest risk of miscarriage; Second trimester (weeks 13-26) is often called the "honeymoon period" when morning sickness eases and the baby bump appears; Third trimester (weeks 27-40) is when the baby gains weight rapidly and prepares for birth.

Is pregnancy 9 months or 10 months?

While pregnancy is often described as 9 months, it's actually closer to 10 lunar months (40 weeks or 280 days). This is because pregnancy is counted from the first day of your last menstrual period, which is typically about 2 weeks before conception actually occurs.

How accurate is the due date calculation?

Due date calculations are estimates. Only about 5% of babies are born on their exact due date. Most babies are born within 2 weeks before or after the due date. First-trimester ultrasound dating is most accurate for confirming due dates.

What is the difference between gestational age and fetal age?

Gestational age counts from the first day of your last menstrual period (LMP) and is the standard used by doctors (40 weeks total). Fetal age (or embryonic age) counts from the actual date of conception, which is typically about 2 weeks after LMP. So if you're 10 weeks pregnant by gestational age, your baby's fetal age is approximately 8 weeks.

When does each trimester start and end?

First trimester: Week 1 to Week 12 (conception through early development). Second trimester: Week 13 to Week 26 (baby movement becomes noticeable). Third trimester: Week 27 to Week 40 (final growth and preparation for birth).

Tips for a Healthy Pregnancy

Prenatal vitamins: Start taking folic acid before conception and throughout pregnancy
Regular checkups: Attend all prenatal appointments as scheduled
Balanced diet: Eat plenty of fruits, vegetables, lean proteins, and whole grains
Stay hydrated: Drink at least 8-10 glasses of water daily
Exercise: Maintain moderate physical activity (consult your doctor first)
Rest: Get adequate sleep, especially during the first and third trimesters
Avoid harmful substances: No alcohol, tobacco, or recreational drugs

When to Contact Your Healthcare Provider

While this calculator helps track your pregnancy, always consult your healthcare provider for medical advice. Contact them immediately if you experience:

Vaginal bleeding or fluid leakage
Severe abdominal pain or cramping
Sudden swelling of face, hands, or feet
Severe headaches or vision changes
Decreased fetal movement (after 28 weeks)
Signs of preterm labor before 37 weeks

Additional Resources

ACOG - How Your Fetus Grows During Pregnancy

Reference this content, page, or tool as:

"How Many Weeks Pregnant Am I?" at https://MiniWebtool.com/how-many-weeks-pregnant-am-i/ from MiniWebtool, https://MiniWebtool.com/

by miniwebtool team. Updated: Jan 30, 2026

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