Getting Pregnant
Ovulation, fertile windows and early signs, explained simply.
- When is the best time to conceive?
- hCG calculator: how many weeks pregnant?
- How to calculate your ovulation day
When did I get pregnant?
Use our conception calculator: enter your last period, due date or conception date to see when you likely conceived and when baby is due.
Find your dates
Free and private Your dates appear here
Pick a date above and you will see when you most likely conceived, your due date and where you are today.
You most likely conceived around
Due date
Today you are
Trimester
More pregnancy calculators
See all pregnancy calculatorsNext steps for pregnant mothers
A positive test starts a long to-do list. Begin with these six, each with a guide that goes through it.
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Work out your due date
Your last period or a scan gives your due date and how many weeks along you are. Everything else is timed from it.
Open the due date calculator -
Start folic acid and a prenatal vitamin
Folic acid in early pregnancy lowers the chance of neural tube defects. Here is how much, and what to look for on the label.
Read the folic acid guide -
Book your first prenatal appointment
Call your doctor or midwife early. This is what the first visit covers and what to ask.
See what to expect -
Check what is safe to eat and drink
The foods, drinks and habits to avoid while pregnant, and what to eat instead.
Read the food safety guide -
Ease the early symptoms
Nausea, tiredness and food aversions are common in the first weeks. These ideas help most people.
Get nausea tips -
Find support near you
Helplines, charities and health services in ten countries, for pregnancy, birth and life with a newborn.
Browse resources by country
Your pregnancy, week by week
Pick any week Start with the week you are in, or read ahead. Each week covers baby's growth, your body and a short to-do list.
Browse all 40 weeks Help for every step
Start with the guide that answers the question on your mind right now.
Pregnancy Timeline
What changes for you and baby, all 40 weeks.
See all 40 weeks
Baby Names
Search 1,500+ names by letter, origin and meaning.
Search names
Diet & Supplements
Nutrients, foods and vitamins that support conception.
Explore nutritionFind a name you love
Search 1,500+ names with origins and meanings. Type a letter or a few letters, then filter by girl, boy, unisex or origin.
When did I get pregnant? How the conception calculator works
Doctors count a pregnancy from the first day of your last period, and conception happens about two weeks later in a typical 28-day cycle. Our conception calculator turns the date you know into a likely conception date. Enter your last period and cycle length, your due date, or a conception date from ovulation tracking or IVF, and it shows the day and a window of a few days either side.
Working back from a due date is the most common way to answer "when did I conceive?". Count back 266 days from the due date and you reach the most likely conception day. If you have a scan report, use the due date it gives, because an early ultrasound is the most accurate way to date a pregnancy.
If you are already counting weeks
Pregnancy weeks include the two weeks before conception, so you conceived about two weeks fewer than you have been pregnant. If you are 5 weeks pregnant, you most likely conceived about 3 weeks ago.
| Weeks pregnant | You most likely conceived about |
|---|---|
| 4 weeks | 2 weeks ago (14 days) |
| 5 weeks | 3 weeks ago (21 days) |
| 6 weeks | 4 weeks ago (28 days) |
| 7 weeks | 5 weeks ago (35 days) |
| 8 weeks | 6 weeks ago (42 days) |
| 9 weeks | 7 weeks ago (49 days) |
| 10 weeks | 8 weeks ago (56 days) |
| 11 weeks | 9 weeks ago (63 days) |
| 12 weeks | 10 weeks ago (70 days) |
Conception, fertilization and implantation
These are three different moments. An egg is fertilized within about a day of ovulation, so your conception date and your date of fertilization are effectively the same day. Implantation comes 6 to 12 days after ovulation, most often on days 8 to 10, and it is when pregnancy hormone starts to build and a test can begin to turn positive. The implantation calculator estimates your window from your last period or ovulation date, and our guide to implantation bleeding explains what you may notice.
Once you know your dates, the due date calculator shows how many weeks pregnant you are today, and the pregnancy calculators page lists every tool we offer.
Conception calculator questions
Short answers about conception dates and how they are worked out.
When did I get pregnant if I am 6 weeks pregnant?
You most likely conceived about 4 weeks ago, around two weeks after the first day of your last period. Enter your dates in the calculator above for the exact day and a window of a few days either side.
Can a calculator tell me exactly when I got pregnant?
Not to the day. Even a scan estimates the date of conception, and a calculator gives your most likely day with a window of a few days either side. If you tracked ovulation or had IVF, enter that conception date and the window narrows.
How accurate is a conception date calculator?
It is an estimate. Ovulation can move from one cycle to the next and sperm can survive for up to five days, so the true day may fall a few days earlier or later. A scan in the first trimester narrows it down.
How do I calculate my conception date from my due date?
Count back 266 days from your due date, which is about 38 weeks. The calculator above does it for you and shows a window around the result.
Is the date of fertilization different from the conception date?
In practice they are the same day. An egg can be fertilized for only about 12 to 24 hours after ovulation, so fertilization happens at or just after ovulation. Implantation comes later, 6 to 12 days after ovulation.
How do I work out when I fell pregnant if my cycles are irregular?
Ovulation is harder to predict with irregular cycles, so a date based on your last period can be off by more than a week. If you have a scan, use the due date it gives and the calculator will count back from it.
Can a conception calculator tell me if I am pregnant?
No. A pregnancy test does that. A calculator estimates dates once you know, or once you want to know when ovulation and conception are likely. Our guide to when to take a pregnancy test explains the timing.
Free weekly help, timed to your due date
One short email each week: what baby is doing, what you may feel and what to ask at your next appointment.