Baby Week Calculator Week by Week

Track your baby's development week by week with our pregnancy timeline calculator. Simply enter your last menstrual period date or estimated due date, and we'll show you what your baby is doing each week of pregnancy.

How to Use This Calculator

Using our baby week calculator is simple:

Enter your last menstrual period (LMP) date or estimated due date (EDD)
Select whether you want to track by LMP or EDD
Click "Calculate" to see your current pregnancy week
Scroll through the timeline to see weekly milestones

For the most accurate results, use your confirmed LMP date from your healthcare provider. If you don't know your LMP, your estimated due date is a good alternative.

Pregnancy Timeline Week by Week

The baby week calculator shows you a detailed timeline of your pregnancy, week by week. Here's what you'll see:

Your current pregnancy week
Expected due date
Fetal development milestones
Common symptoms and concerns
Recommended prenatal care visits

Formula used:

If tracking by LMP: Current week = (Days since LMP / 7) + 1

If tracking by EDD: Current week = (Days until EDD / 7) - 40

For example, if you're 12 weeks pregnant, you'll see:

Your baby is about the size of a lime
Fingers and toes are forming
Your baby's heart rate is now detectable
Common symptoms include nausea, fatigue, and mood swings

Fetal Development Stages

Our calculator breaks down fetal development into key stages:

Week Range	Development Milestones	Baby Size
1-4	Implantation, organ formation, rapid growth	Tiny, not yet visible
5-8	Limbs forming, heart beating, face developing	Grape size
9-12	Fingers and toes forming, heart rate detectable	Lime size
13-16	Eyes forming, movement detectable, hair growing	Plum size
17-20	Lungs developing, bones hardening, fat storing	Turnip size
21-24	Brain developing, eyes opening, practicing breathing	Carrot size
25-28	Skin forming, hair growing, practicing breathing	Potato size
29-32	Eyes opening, practicing breathing, fat storing	Cabbage size
33-36	Lungs maturing, bones hardening, practicing breathing	Watermelon size
37-40	Full-term baby, ready for birth	Full-term size

Common Concerns by Week

Our calculator also highlights common concerns and symptoms for each week of pregnancy:

First trimester (1-12 weeks): Nausea, fatigue, mood swings
Second trimester (13-28 weeks): Back pain, heartburn, varicose veins
Third trimester (29-40 weeks): Shortness of breath, swelling, Braxton Hicks contractions

Remember that everyone's pregnancy is different. If you have concerns about symptoms or development, always consult with your healthcare provider.

Frequently Asked Questions

How accurate is the baby week calculator?

Our calculator provides an estimate based on standard pregnancy timelines. For the most accurate information, always consult with your healthcare provider.

Can I use this calculator if I'm pregnant with twins or multiples?

Our calculator is designed for singleton pregnancies. If you're expecting twins or multiples, your healthcare provider can provide more specific guidance.

What should I do if my baby's development seems delayed?

If you notice any concerns about your baby's development, contact your healthcare provider immediately. They can perform tests to monitor your baby's growth.

How often should I use the pregnancy week calculator?

You can use our calculator as often as you like to track your baby's development. It's especially helpful to check weekly during your prenatal visits.