Pregnancy Calculator - Due Date, Weeks & Schedule

Getting ready for a baby is just the best, right? But honestly, trying to keep track of the whole timeline feels impossible sometimes. Seriously, when are you due? How far along are we today? That’s exactly why we cooked up this pregnancy calculator. It just takes the guesswork out of all those gestational dates. You can use it to map out maternity leave, figure out when the next checkup should be, or maybe you’re just nosey—totally fine! We made sure you can use whatever piece of info you have: your last period date, an early scan result, or even if you nailed down the exact conception day.

Enter Details

First day of last period (LMP)

Result

Choose your LMP date. This uses a standard 280-day rule — not a substitute for prenatal care.

Note — This result is an estimate. Talk to a healthcare provider for personalized guidance.

How to Use This Pregnancy Calculator

Look, we know not everyone tracks things the same way. Some calculators *only* care about your Last Menstrual Period (LMP), but we get that modern tracking often involves more specific dates.

Just pick the calculation method below that matches the most reliable date you've got. Put the date in, and boom—the tool instantly spits out your estimated due date, what week you’re in right now, and a rough idea of what’s next.

Calculate by Due Date

If you’ve already had one of those early ultrasounds that gave you a preliminary Estimated Due Date (EDD), this is the fastest route. Plug that date in, and this thing will work backward to tell you when your pregnancy probably kicked off and where you stand this week.

Calculate by Last Menstrual Period (LMP)

This is the tried-and-true way, the classic method. You just need the very first day of your last period. If your cycles are pretty regular—like, every 28 days—this estimate for your due date is usually spot on initially.

Calculate by Conception Date

If you happen to know the exact moment conception happened—maybe you track ovulation religiously or timed things perfectly—using that date gives you the most precise starting point for the baby’s actual age. Just a quick note though: doctors still calculate gestational age starting from your LMP, so they'll always be two weeks ahead.

Calculate by Ultrasound Date

Ultrasounds done really early in the first trimester (usually between 8 and 13 weeks) are fantastic for accurate dating. Give us the date of that scan and, if you have it, the crown-rump length measurement, and we’ll tighten up that schedule for you.

Calculate by IVF Transfer Date

For folks going through IVF, the transfer date is a super important anchor point. Enter that date, and we’ll use the standard medical protocol to figure out your starting gestational week and that target due date.

How to Calculate Your Due Date

Figuring out that magic due date is really the core of all pregnancy planning. Heads up, though, it’s just an estimate. Seriously, only about 5% of babies show up exactly on their due date. But it’s the main benchmark doctors use to track growth and schedule necessary tests.

Naegele's Rule - The Standard Due Date Formula

Most doctors use Naegele's Rule; it’s straightforward and only requires your LMP. Here’s the breakdown:

Start with the first day of your Last Menstrual Period (LMP).
Go back three months from that date.
Now, add seven days to whatever date you land on.
Don't forget to bump the year up if you crossed over into the next one!

For example: Let’s say your LMP started November 15, 2024. You’d count back to August 15, 2024, and then add 7 days. That puts your estimated due date around August 22, 2025. Pretty neat trick, right?

How Accurate Is Your Due Date?

You absolutely have to keep in mind that the due date is just a really educated guess—it's aimed at 40 weeks from when your period started. While those early ultrasounds tend to be the best dating tool, especially if your cycles are all over the place, very few babies stick strictly to that 40-week deadline. In fact, full-term is officially anything between 37 and 42 weeks, so try not to freak out if your little one arrives a bit early or decides to stay put a few days late!

How Many Weeks Pregnant Am I?

This is the question you hear constantly, and the answer depends on which system everyone is using. When your doctor says, “You’re 10 weeks pregnant,” they aren't saying the baby has been growing for ten weeks. Nope. They are referring to the total time that has passed since the first day of your LMP. That standardized system is what dictates the whole prenatal care schedule.

Gestational Age vs Fetal Age - What’s the Difference?

This part trips up a lot of people, but it clicks fast once you get the hang of the terminology:

Gestational Age: This is the official medical number. It starts counting from your LMP. This total generally hits 40 weeks.
Fetal Age (or Conception Age): This measures the actual time the embryo or fetus has been developing in there. Since conception usually happens about two weeks after the LMP starts, the fetal age is almost always two weeks less than the gestational age. So, if you are technically 12 weeks pregnant (gestational), the baby has only been actively growing for about 10 weeks (fetal age).