Explore pregnancy week by week. This free pregnancy week calculator shows the trimester, month, progress and typical milestones for any week from 1 to 42.
A general week-by-week guide for information only. Every pregnancy is different, and the notes here are typical milestones, not predictions. Your midwife or doctor is your best source for what’s happening in your pregnancy.
Pregnancy week
of 40
Enter or slide to any week from 1 to 42 to see the trimester, the pregnancy month, how far along that is, and what’s typically happening. To work out your current week from a date, use the Pregnancy Calculator.
Week
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Choose a week
Trimester
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Month
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Weeks to 40
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Progress
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Typically around this week
General educational information, not medical advice. For care and anything specific to your pregnancy, speak with your midwife or doctor.
Use this free pregnancy week calculator to explore any week of pregnancy. Pick a week from 1 to 42 to see the trimester, the pregnancy month, how far along it is and what typically happens.
What this pregnancy week calculator does
This pregnancy week calculator is a week-by-week guide. For any week you choose, it shows the trimester, the month, weeks remaining to 40, your progress and a short note on what’s usually happening then.
Pregnancy weeks, months and trimesters
Weeks
Month
Trimester
1 – 13
1 – 3
First
14 – 27
4 – 6
Second
28 – 40
7 – 9
Third
Pregnancy is counted in weeks rather than months because weeks are more precise — 40 weeks is a little longer than nine calendar months.
Want your current week from a date?
If you’d rather work out exactly how far along you are today from your last period or due date, use the Pregnancy Calculator — it does the date maths for you. This page is for browsing what each week looks like.
How to use the pregnancy week calculator
Enter a week (1–42) or drag the slider.
See the trimester, month and progress.
Read the typical milestone for that week.
Pregnancy Week FAQ
How many weeks are in a pregnancy?
About 40 weeks, counted from the first day of your last period. Full term is from 37 weeks, and birth can happen normally any time up to 42 weeks.
How do weeks map to trimesters?
First trimester is weeks 1–13, second is 14–27, and third is 28 onward. This calculator labels the trimester for any week you pick.
How do I know what week I'm in right now?
Work it out from your last period or due date using the Pregnancy Calculator, which does the date maths. This page lets you browse what each week looks like.
Why is pregnancy measured in weeks not months?
Weeks are more precise, since 40 weeks is slightly longer than nine calendar months and months vary in length.
Are the weekly milestones exact?
No — they're typical, general guides. Every pregnancy develops at its own pace, and your midwife or doctor is the best source for your specifics.
Is the pregnancy week calculator free?
Yes, this pregnancy week calculator is completely free, needs no sign-up, and works instantly in your browser.
