All tools
Pregnancy week calculator
How many weeks and days pregnant you are today, the trimester and the days to go. Free, with no account or uploads.
How far along you are
Type the first day of your last period, or the due date you were given.
Counting from
Last periodDue date givenConceptionIVF transferA scan
From the first day of one period to the first day of the next.
Type a date to see the answer.
This is arithmetic on your numbers, not medical advice; ask a doctor, nurse or midwife about your own health. Worked out in your browser; nothing you type is sent anywhere or kept, and this page has no adverts.
A little help along the way
Follow these steps. Every option is explained underneath. Everything runs in your browser; nothing is sent anywhere or kept.
- Say what you want to work outA due date, how far along you are, the conception date, or your fertile days.
- Say what you are counting fromYour last period, a due date you were given, conception, an IVF transfer or a scan.
- Type the dateWith your usual cycle length for a period, the embryo's age for IVF, or the age a scan gave.
- Read the answerIn words, with the rule it was counted by; add a due date to your calendar.
Questions people ask
- How are pregnancy weeks counted?
- From the first day of the last period, about two weeks before conception, so 12 weeks pregnant is about 10 weeks after conception.
- When does each trimester start?
- The second at 14 weeks and the third at 28 weeks, as ACOG counts them.
- Can I count from my due date?
- Yes. Choose Due date given and type it; the weeks are counted back from it.
This page is the Pregnancy calculator, opened for this one job; every other tool it has is one press away. Each of its settings is explained on the Pregnancy calculator's own page.
Read the step-by-step guide