The Best Ovulation, Conception, And Pregnancy Calculators For Every Mom-To-Be


The entire pregnancy process, from conception to birth, can be a lot to manage. That’s probably why there’s a multi-million dollar industry of products devoted to pregnancy planning. But one invaluable pregnancy resource is completely free – pregnancy calculators! Pregnancy calculators and conception calculators can be the linchpin of a smooth family planning process.

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But which pregnancy calculators are right for you?

In this post, I break down the best pregnancy and conception calculators to get you from pre-conception to postpartum without a hitch.

*Please note: this post will help you sort through the many resources and pregnancy calculators out there. It’s not medical advice. If you have a medical question or concern, be sure to see your doctor or other qualified medical professional.

Getting Started: Ovulation Calculators and Conception Calculators

There are so many choices when it comes to conception calculators. In the end, it comes down to personal preference, but my best recommendation to you is the Baby Center Ovulation Calendar.


First, it’s simple to use. All you need to do is enter the date of your last period and your average cycle length.

Second, it lets you adjust your cycle length from the default 28 days. Some calculators don’t include this option and it makes your results less accurate.

(According to this recent study, only about 13% of women’s cycles are actually 28 days in length. Let’s all take a minute to express our complete and total shock that women’s reproductive cycles have been largely misunderstood for ages. I’ll wait. . .)

Third–and most important–this particular ovulation calendar gives you your fertile window for the month you request, as well as the five following months. This is great because you’ll know all your possible fertile windows and potential due dates.

(If you really want to nail down your fertile window, you can use simple ovulation tests like these.)

Pregnancy Test Calculators

Let’s assume the trying is already underway. The deed has been done, if you will. You’ve used the ovulation calculator to find your fertile window. Now you want to know if it worked!

Anyone who’s ever tried to conceive knows about the dreaded two-week wait. It’s the two weeks between when you ovulate and when you expect your period to arrive. The hope is that you’ve successfully conceived and that period never comes.

If you’re trying to conceive, you probably spend those two weeks compulsively wondering if you’re pregnant. Every twinge, every gas bubble sets off a chain reaction in your pregnancy-obsessed mind. What was that? Does this mean I’m pregnant?!

But how early is too early to test? Well, there’s a pregnancy calculator for that!

My favorite pregnancy test calculator is from ClearBlue Easy. It will tell you when you can possibly expect a positive pregnancy test from the most sensitive tests. Scrolling down the page, it also provides a graph showing how the hCG in your urine changes as the days of a pregnancy continue.

If you want to test as early as humanly possible, you’re going to need a very sensitive test, like this one from First Response. This one from Clear Blue Easy can also get the job done. 

If you have more self control than I do, and can wait a few days, you can use cheaper pregnancy tests like these. Even the dollar store has pregnancy tests that are pretty reliable after you’ve missed your period.

A runner-up pregnancy test calculator is this one from Baby Med. I like this one because it’s straight forward and it doesn’t over-promise.

The earliest date provided by Clear Blue Easy’s calculator will still give many pregnant women a negative result. There just won’t be enough hCG present in the urine for everyone so early.

The dates given in Baby Med’s pregnancy calculator are less likely to provide false negatives. Plus, it differentiates between the dates a blood test would come up positive as compared to a urine test. Blood tests can typically detect a pregnancy a few days earlier.

pregnancy tests

Pregnancy Week-by-Week Calculators: How Many Weeks Pregnant Am I?

Let’s assume the test is positive. Congratulations!

You might be wondering how many weeks pregnant you are. This can be a little tricky because you’re already considered four weeks pregnant when you miss your period. Think of it like two weeks of extra credit. (Who doesn’t like extra credit?!)

Your instincts will probably be to count forward from the time of conception. But that’s not how the medical community views your pregnancy. The sooner you can get on the same page, the better off you’ll be.

That’s where a week-by-week pregnancy calculator comes in handy.

You can enter your due date or the date of your last period and get a detailed breakdown of your pregnancy. Even better, you can enter your email and the weekly updates will be sent right to your inbox.

Both What to Expect and Baby Center have excellent pregnancy week-by-week calculators you may want to consider.

If you want a very technical pregnancy calculator, Baby Med also has an option. What’s great about this particular pregnancy calculator is how detailed it is. What’s not so great about this pregnancy calculator is . . . how detailed it is.

Baby Med’s calculator uses a variety of drop-down menus. It can tell you how many days and weeks pregnant you are and when you should have your various ultrasounds and other screening tests. It can even tell you how much your baby should weigh, down to the gram, EACH DAY.

If you find it reassuring to have access to that much information at your fingertips, you’ll probably love this pregnancy calculator. If you find it overwhelming to have more information than you need (and this pregnancy calculator definitely gives you more than you need), it’s probably best to skip this one.

One Last Type of Pregnancy Calculator – The Date of Conception Calculator

Up until now, we’ve been moving chronologically. At this point, it’s time to work backward.
Suppose you’re pregnant, you’ve been to the doctor, and you know your due date. What you don’t know is when you actually conceived.

This date of conception calculator from is perfect for this kind of thing. Simply enter your due date and it will tell you when you conceived.

Baby Center doesn’t have a calculator geared specifically toward date of conception. However, their regular week-by-week pregnancy calculator includes an estimated date of conception.

In the scheme of things, the pregnancy calculators are the easiest part!

When you’re trying to get pregnant, and even once you are pregnant, the planning can feel overwhelming. There are so many apps, checklists, and calculators meant to help you plan your pregnancy. Try not to get too overwhelmed in the planning stage. Once baby is on the scene, well, that’s when the real fun (and craziness) begins.

I hope you find these pregnancy calculators helpful as you navigate this exciting journey!


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