Pregnancy Due Date Ranges

This table attempts to estimate your probability of going into labor on different individual days based on your estimated due date. If you don't know your due date, or just want a handy daily page to tell you where you're at, use the pregnancy calendar.

It's based on the idea that the average pregnancy lasts 40 weeks with a standard deviation of about 10 days. This means you're more likely to go into labor on one of the days close to your due date. For instance, about half of all babies are born within a week of their date. Scroll to the bottom of this page if you want to know more about where I got these numbers.

The following dates are based on an estimated due date of May 24th, 2016.

Change due date:
Month Day Year
Date Progress Overall probability of
spontaneous labor
Current probability of
spontaneous labor
probability of a pregnant woman at this stage going into labor
On this date By this date On this date By this date On this date Within 3 days Within 5 days Within 7 days
Tuesday April 19th, 2016 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Wednesday April 20th, 2016 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Thursday April 21st, 2016 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Friday April 22nd, 2016 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Saturday April 23rd, 2016 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Sunday April 24th, 2016 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Monday April 25th, 2016 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Tuesday April 26th, 2016 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Wednesday April 27th, 2016 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Thursday April 28th, 2016 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Friday April 29th, 2016 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Saturday April 30th, 2016 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Sunday May 1st, 2016 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Monday May 2nd, 2016 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Tuesday May 3rd, 2016 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Wednesday May 4th, 2016 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Thursday May 5th, 2016 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Friday May 6th, 2016 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Saturday May 7th, 2016 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Sunday May 8th, 2016 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Monday May 9th, 2016 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Tuesday May 10th, 2016 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Wednesday May 11th, 2016 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Thursday May 12th, 2016 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Friday May 13th, 2016 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Saturday May 14th, 2016 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Sunday May 15th, 2016 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Monday May 16th, 2016 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Tuesday May 17th, 2016 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Wednesday May 18th, 2016 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Thursday May 19th, 2016 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Friday May 20th, 2016 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Saturday May 21st, 2016 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Sunday May 22nd, 2016 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Monday May 23rd, 2016 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Tuesday May 24th, 2016 40W, 0D 3.99% 50% 8% 0% 8% 23.6% 38.3% 51.6%
Wednesday May 25th, 2016 40W, 1D 3.97% 53.98% 7.9% 8% 8.6% 25.1% 40.4% 54%
Thursday May 26th, 2016 40W, 2D 3.91% 57.93% 7.8% 15.9% 9.3% 26.7% 42.5% 56.2%
Friday May 27th, 2016 40W, 3D 3.81% 61.79% 7.6% 23.6% 10% 28.2% 44.5% 58.5%
Saturday May 28th, 2016 40W, 4D 3.68% 65.54% 7.4% 31.1% 10.7% 29.8% 46.6% 60.6%
Sunday May 29th, 2016 40W, 5D 3.52% 69.15% 7% 38.3% 11.4% 31.3% 48.6% 62.7%
Monday May 30th, 2016 40W, 6D 3.33% 72.57% 6.7% 45.1% 12.1% 32.9% 50.5% 64.7%
Tuesday May 31st, 2016 41W, 0D 3.12% 75.8% 6.2% 51.6% 12.9% 34.4% 52.4% 66.6%
Wednesday June 1st, 2016 41W, 1D 2.9% 78.81% 5.8% 57.6% 13.7% 36% 54.3% 68.5%
Thursday June 2nd, 2016 41W, 2D 2.66% 81.59% 5.3% 63.2% 14.4% 37.5% 56.1% 70.2%
Friday June 3rd, 2016 41W, 3D 2.42% 84.13% 4.8% 68.3% 15.2% 39% 57.9% 71.9%
Saturday June 4th, 2016 41W, 4D 2.18% 86.43% 4.4% 72.9% 16.1% 40.5% 59.6% 73.5%
Sunday June 5th, 2016 41W, 5D 1.94% 88.49% 3.9% 77% 16.9% 42% 61.3% 75.1%
Monday June 6th, 2016 41W, 6D 1.71% 90.32% 3.4% 80.6% 17.7% 43.4% 62.9% 76.4%
Tuesday June 7th, 2016 42W, 0D 1.5% 91.92% 3% 83.8% 18.6% 44.8% 64.5% 77.8%
Wednesday June 8th, 2016 42W, 1D 1.3% 93.32% 2.6% 86.6% 19.5% 46.3% 65.9% 79.2%
Thursday June 9th, 2016 42W, 2D 1.11% 94.52% 2.2% 89% 20.3% 47.6% 67.3% 80.5%
Friday June 10th, 2016 42W, 3D 0.94% 95.54% 1.9% 91.1% 21.1% 48.9% 68.8% 81.6%
Saturday June 11th, 2016 42W, 4D 0.79% 96.41% 1.6% 92.8% 22% 50.1% 70.2% 82.7%
Sunday June 12th, 2016 42W, 5D 0.66% 97.13% 1.3% 94.3% 23% 51.6% 71.4% 83.6%
Monday June 13th, 2016 42W, 6D 0.54% 97.72% 1.1% 95.4% 23.7% 53.1% 72.8% 84.6%
Tuesday June 14th, 2016 43W, 0D 0.44% 98.21% 0.9% 96.4% 24.6% 54.2% 73.7% 85.5%
Wednesday June 15th, 2016 43W, 1D 0.35% 98.61% 0.7% 97.2% 25.2% 55.4% 74.8% 86.3%
Thursday June 16th, 2016 43W, 2D 0.28% 98.93% 0.6% 97.9% 26.2% 56.1% 75.7% 87.9%
Friday June 17th, 2016 43W, 3D 0.22% 99.18% 0.4% 98.4% 26.8% 57.3% 76.8% -%
Saturday June 18th, 2016 43W, 4D 0.18% 99.38% 0.4% 98.8% 29% 58.1% 79% -%
Sunday June 19th, 2016 43W, 5D 0.14% 99.53% 0.3% 99.1% 29.8% 59.6% -% -%
Monday June 20th, 2016 43W, 6D 0.1% 99.65% 0.2% 99.3% 28.6% 62.9% -% -%
Tuesday June 21st, 2016 44W, 0D 0.08% 99.74% 0.2% 99.5% 30.8% -% -% -%
Wednesday June 22nd, 2016 44W, 1D 0.06% 99.81% 0.1% 99.6% 31.6% -% -% -%
Thursday June 23rd, 2016 44W, 2D 0.04% 99.87% 0.1% 99.7% 30.8% -% -% -%

Probability of labor on a given day

Probability of labor by a given day

Notes and disclaimers

All percentages are estimates based on mathematical averages and should not be taken terribly seriously... just because you only have 5% chance of going into labor two weeks early, that doesn't mean you should schedule a trip to the bahamas that weekend (see xkcd to get what I mean here).

You should (obviously) listen to your doctor or midwife on all matters related to pregnancy and childbirth. Just because this chart tells you that a 42W pregnant woman has a high chance of delivering in the next seven days, it doesn't mean it's healthy for her to be pregnant for seven more days. If your doctor wants to increase probability of delivery by inducing labor, there's probably a good reason.

Finding good distribution statistics on spontaneous labor is interesting. I have not found a study with an exact daily breakdown of when babies are born. However I have read way too much on this topic, so I can tell you that my favorite published research is The length of human pregnancy as calculated by ultrasonographic measurement of the fetal biparietal diameter (H. Kieler, O. Axelsson, S. Nilsson, U. Waldenströ) which a very nice table of 10 published studies, which found various means between 272-283 days. The study contributes their own results as well, analyzing nearly 2000 mothers who went into labor spontaneously, and there's graphs of what they found. They found a mean around 280 days, and standard deviations between 8-11 days. There's a big list of other studies and answers in the Introduction to my due date survey results.

Which leads to this topic... I am also in the process of collecting my own statistics. If you have had a baby, please take my due date survey. Oddly enough, the numbers I've collected so far support my messy hunch that pregnancy length has a 40-week mean and 9-10 day standard deviation. So go me.

Anyway if you have better research, drop me an e-mail (spacefem@spacefem.com).

Charts are generated by flot.

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Recent Comments

For more support, encouragement, Q&A, you are invited to join our pregnancy forum. We are dedicated to answering complicated questions as logically as we possibly can.

Kids are full of LIES

Sun May 22 2:29 PM by rowan in Pregnancy & Parenting

Don't be silly monk, everyone knows a good conglomerate goes better with milk


Pregnancy Guidebooks for Cool Moms (humor)

Wed May 11 3:39 PM by rowan in Pregnancy & Parenting

One of my friends is part of this magazine. She didn't write this one but it's pretty hilarious.

http://theoffingmag.com/wits-end/pregna ... cool-moms/

Anyone want to come up with our own "Guidebook" titles?

spoiler:
the one about inducing labor by setting your hair on fire is my favorite


stuttering at the end of words

Thu Apr 28 9:21 PM by Sonic# in Pregnancy & Parenting

I don't think it's a cause for immediate concern, but my experience would lead me to talk to a doctor about it. I didn't have a stutter when I was 2. I had language delay. I didn't learn language when kids typically do. Needless to say, I was a very frustrated little kid. When my parents and my pediatrician caught on to it, I had to spend a few years seeing a speech pathologist.

I've read that stuttering is at least partly psychological, but I really can't say more than that. If nothing else, I'd just want to know that his frustration is a necessary part of development like teething and not something that can be avoided.


Criminalization of drug use during pregnancy to end in Tennessee

Tue Mar 29 2:48 AM by Amuro in Pregnancy & Parenting

Actually I think it would be better if the penalty was rehab and being sent to a therapist. It's pretty dumb to criminalize it especially because there is an almost certainty custody will be taken away. Why not try and fix the problem with addiction so there is less of a strain on social services. There should be increased awareness but what idiot doesn't know drugs are bad for you and worse if your pregnant. If you are addicted to drugs you obviously are thinking about getting high and that's about it.


Why have children if you want to work (aka it's 1950!)

Tue Mar 8 9:16 PM by antfancier in Pregnancy & Parenting

I just had a look at your article. :thumbup:
As you say, many comments have been deleted, but that's probably for the best otherwise I'd get mad.

I'm about to have my first child and have had some similarly surprising responses from people when I explain I'm going to be a SAHM; everything from admiration to unsolicited suggestions that a nanny is better than daycare. When I explain that the reason is that I acut ally want to work but my earnings from my two part time jobs would barely cover childcare, it always gets awkward. And then they suggest the whole home daycare/nanny thing again. Even if I could afford it, I'd rather choose the daycare because they have facilities and resources that I don't (I live in a basement apartment, with pretty minimalist furnishings).

I get it. People have strong beliefs about what is 'best', but it's not a one-size-fits-all scenario. And holy crap! If a woman wants and is able to work after having kids, why on earth shouldn't she?


it gets better thread for parents

Mon May 16 2:44 PM by Sassquatch in Pregnancy & Parenting

I'll take more posts here! I'm almost ready to give birth to my second, and I swear some parts are less scary because I know what's coming, but most of it is more scary because I do. What I do wish I'd really understood the first time is how short all the horrible baby phases are, in the long run, and how little you care about mommy wars BS like formula/breast milk after a very brief time.


young kids, consent and bodily autonomy

Mon May 2 8:46 PM by monk in Pregnancy & Parenting

I think it depends on the child. Do you ask a newborn if it needs it's diaper changed? Obviously no. Do you help a 13 year old get dressed? Obviously no. Somewhere in there the child matures to the point where they should learn that they own their bodies even if they don't have all the privileges an adult does. This age is going to vary wildly between different children (by widly, I would say 3 year range). I would guess that some kids might be ready for this lesson as early as 3 while others not until they're about to go school. Actually that's a pretty good benchmark, because if you're going to put them in a group with other kids they don't know they should know the rules about touching or being touched.

As far as kissing Grandma, maybe they shouldn't have to do it, but making them do this social communcation helps get them ready for all the other social communication that will be forced on them later. Plus, grandma needs that love to help HER be healthy.


Umbilical cord

Wed Apr 27 1:26 AM by antfancier in Pregnancy & Parenting

There's a Bulgarian tradition about the umbilical cord my friend told me about. When the dried little stump falls off your baby, you're supposed to throw it in a place that reflects your child's future, or at least the future you want for them. My friend threw his first son's on to the pitch at a Yankees' game and for his second son he threw it at the stage during a concert!

When my son's cord fell off a few weeks ago, I put it on the counter next to his changing pad then promptly forgot about it. I've no idea where it is now.


Pets and newborns

Tue Mar 22 2:34 AM by codingchemist in Pregnancy & Parenting

It's really obvious that the dog is stressed out by the toddler and I'm worried about the times when the kid is showing too much interest in the dog and we're not paying enough attention.

Yeah-stressed out dogs can make for stressful times with toddlers. Toddlers just want to pet and hug, and don't want to listen to pleas to leave the dog alone. We wound up getting an automatic treat dispenser and giving the dog relaxation exercises behind a barrier. So now when the toddler is running the length of the house screaming, the dog can be behind the barrier staring lovingly at her treat dispenser, instead of trying to herd the kid. Of course, it isn't really feasible to keep the dog behind the barriers at all times, but at least it gives us some breaks.

Our behavioralist also recommended Prozac, which took a long time to get the dose right, but has helped the dog be less reactionary and neurotic.


Party For My Mom

Thu Mar 3 10:36 PM by curlybae in Pregnancy & Parenting

Hi! It's a great idea to throw a party for your Mom. So yeah, invite her good friends and those who she hasn't seen for quite some time already. Prepare some healthy food or you can get a caterer for this tell them to prepare your mom's favorite dishes. Set up a good sound system where they can opt to dance or sing their old fav songs. Request her friends to prepare a great birthday greetings and i'm sure she won't forget this event.


minimalist kids birthday parties

Sun May 15 9:19 PM by melsbells in Pregnancy & Parenting

For the first two birthdays, we tried to make some special food and splurge on interesting fruit. If I lived closer to friends, I would want to throw a get-together as an excuse to see my friends, celebrate our survival of another year. I don't think my kid would actually be into that though. They are turning out to be quite introverted and shy.


7th Birthday - Theme Suggestion

Mon May 2 8:18 PM by melsbells in Pregnancy & Parenting

I met a kid about that age who had a geo-caching birthday party and another one who had a roller-skating party. Both sounded awesome. The first one sounded like a whole lot of work to put together.


test out my new name picker

Fri Apr 15 11:41 PM by rowan in Pregnancy & Parenting

my neighbor's dog is named Gunner? Makes more sense for a bird dog....


Sperm Can be Cultivated from Skin Cells

Thu Mar 10 6:56 PM by rowan in Pregnancy & Parenting

Pretty sure this was a spam post but the post itself is kind of interesting. Maybe it could go to Sci & Tech, though it has relevance here as well. I added a link to the Science article, in case anyone wants to read it.


Advice on dealing with a sick baby

Mon Feb 22 5:28 PM by rowan in Pregnancy & Parenting

oh re: diaper rash, we found our kiddo was super sensitive and when things go really bad we got something prescribed from the doc that worked *wonders*. IDEK why that stuff isn't marketed, the pharmacist mixed it all up. The doc called it "poop goop" but I dunno what was in it.