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 December 20th, 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 November 15th, 2016 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Wednesday November 16th, 2016 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Thursday November 17th, 2016 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Friday November 18th, 2016 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Saturday November 19th, 2016 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Sunday November 20th, 2016 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Monday November 21st, 2016 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Tuesday November 22nd, 2016 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Wednesday November 23rd, 2016 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Thursday November 24th, 2016 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Friday November 25th, 2016 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Saturday November 26th, 2016 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Sunday November 27th, 2016 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Monday November 28th, 2016 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Tuesday November 29th, 2016 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Wednesday November 30th, 2016 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Thursday December 1st, 2016 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Friday December 2nd, 2016 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Saturday December 3rd, 2016 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Sunday December 4th, 2016 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Monday December 5th, 2016 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Tuesday December 6th, 2016 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Wednesday December 7th, 2016 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Thursday December 8th, 2016 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Friday December 9th, 2016 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Saturday December 10th, 2016 38W, 4D 2.42% 15.87% 2.8% 2.7% 2.9% 9.9% 17.8% 26.6%
Sunday December 11th, 2016 38W, 5D 2.66% 18.41% 3.1% 5.6% 3.3% 11.1% 19.7% 29%
Monday December 12th, 2016 38W, 6D 2.9% 21.19% 3.4% 8.8% 3.7% 12.3% 21.6% 31.5%
Tuesday December 13th, 2016 39W, 0D 3.12% 24.2% 3.6% 12.3% 4.1% 13.5% 23.6% 34%
Wednesday December 14th, 2016 39W, 1D 3.33% 27.43% 3.9% 16% 4.6% 14.9% 25.6% 36.6%
Thursday December 15th, 2016 39W, 2D 3.52% 30.85% 4.1% 20% 5.1% 16.2% 27.7% 39.2%
Friday December 16th, 2016 39W, 3D 3.68% 34.46% 4.3% 24.2% 5.6% 17.6% 29.8% 41.7%
Saturday December 17th, 2016 39W, 4D 3.81% 38.21% 4.4% 28.5% 6.2% 19.1% 31.9% 44.2%
Sunday December 18th, 2016 39W, 5D 3.91% 42.07% 4.5% 33% 6.7% 20.6% 34% 46.7%
Monday December 19th, 2016 39W, 6D 3.97% 46.02% 4.6% 37.5% 7.4% 22.1% 36.2% 49.2%
Tuesday December 20th, 2016 40W, 0D 3.99% 50% 4.6% 42.1% 8% 23.6% 38.3% 51.6%
Wednesday December 21st, 2016 40W, 1D 3.97% 53.98% 4.6% 46.8% 8.6% 25.1% 40.4% 54%
Thursday December 22nd, 2016 40W, 2D 3.91% 57.93% 4.5% 51.3% 9.3% 26.7% 42.5% 56.2%
Friday December 23rd, 2016 40W, 3D 3.81% 61.79% 4.4% 55.8% 10% 28.2% 44.5% 58.5%
Saturday December 24th, 2016 40W, 4D 3.68% 65.54% 4.3% 60.1% 10.7% 29.8% 46.6% 60.6%
Sunday December 25th, 2016 40W, 5D 3.52% 69.15% 4.1% 64.3% 11.4% 31.3% 48.6% 62.7%
Monday December 26th, 2016 40W, 6D 3.33% 72.57% 3.9% 68.3% 12.1% 32.9% 50.5% 64.7%
Tuesday December 27th, 2016 41W, 0D 3.12% 75.8% 3.6% 72% 12.9% 34.4% 52.4% 66.6%
Wednesday December 28th, 2016 41W, 1D 2.9% 78.81% 3.4% 75.5% 13.7% 36% 54.3% 68.5%
Thursday December 29th, 2016 41W, 2D 2.66% 81.59% 3.1% 78.7% 14.4% 37.5% 56.1% 70.2%
Friday December 30th, 2016 41W, 3D 2.42% 84.13% 2.8% 81.6% 15.2% 39% 57.9% 71.9%
Saturday December 31st, 2016 41W, 4D 2.18% 86.43% 2.5% 84.3% 16.1% 40.5% 59.6% 73.5%
Sunday January 1st, 2017 41W, 5D 1.94% 88.49% 2.2% 86.7% 16.9% 42% 61.3% 75.1%
Monday January 2nd, 2017 41W, 6D 1.71% 90.32% 2% 88.8% 17.7% 43.4% 62.9% 76.4%
Tuesday January 3rd, 2017 42W, 0D 1.5% 91.92% 1.7% 90.7% 18.6% 44.8% 64.5% 77.8%
Wednesday January 4th, 2017 42W, 1D 1.3% 93.32% 1.5% 92.3% 19.5% 46.3% 65.9% 79.2%
Thursday January 5th, 2017 42W, 2D 1.11% 94.52% 1.3% 93.7% 20.3% 47.6% 67.3% 80.5%
Friday January 6th, 2017 42W, 3D 0.94% 95.54% 1.1% 94.8% 21.1% 48.9% 68.8% 81.6%
Saturday January 7th, 2017 42W, 4D 0.79% 96.41% 0.9% 95.8% 22% 50.1% 70.2% 82.7%
Sunday January 8th, 2017 42W, 5D 0.66% 97.13% 0.8% 96.7% 23% 51.6% 71.4% 83.6%
Monday January 9th, 2017 42W, 6D 0.54% 97.72% 0.6% 97.4% 23.7% 53.1% 72.8% 84.6%
Tuesday January 10th, 2017 43W, 0D 0.44% 98.21% 0.5% 97.9% 24.6% 54.2% 73.7% 85.5%
Wednesday January 11th, 2017 43W, 1D 0.35% 98.61% 0.4% 98.4% 25.2% 55.4% 74.8% 86.3%
Thursday January 12th, 2017 43W, 2D 0.28% 98.93% 0.3% 98.8% 26.2% 56.1% 75.7% 87.9%
Friday January 13th, 2017 43W, 3D 0.22% 99.18% 0.3% 99.1% 26.8% 57.3% 76.8% -%
Saturday January 14th, 2017 43W, 4D 0.18% 99.38% 0.2% 99.3% 29% 58.1% 79% -%
Sunday January 15th, 2017 43W, 5D 0.14% 99.53% 0.2% 99.5% 29.8% 59.6% -% -%
Monday January 16th, 2017 43W, 6D 0.1% 99.65% 0.1% 99.6% 28.6% 62.9% -% -%
Tuesday January 17th, 2017 44W, 0D 0.08% 99.74% 0.1% 99.7% 30.8% -% -% -%
Wednesday January 18th, 2017 44W, 1D 0.06% 99.81% 0.1% 99.8% 31.6% -% -% -%
Thursday January 19th, 2017 44W, 2D 0.04% 99.87% 0% 99.8% 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

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Academic redshirting

Wed Dec 7 8:22 PM by Nachos in Pregnancy & Parenting

I'm on the fence about this. I was always the youngest in my class because I was born 2 days before the cut off. I started school JUST after my 5th birthday (Go England.... not...) and this made a huge gap between me and the oldest kids in the class who were almost a whole year older. However, even though I might have struggled more then I'm ok now, you know? It might have even been helpful for me, pushing myself to learn more and try and be smarter. My sister was held back for a year in preschool in Germany because she didn't speak German well enough for the first grade and so she has always been the oldest in class and she's not really as academic as me. This is all anecdata of course, but interesting to ponder over.


Parents Warned they Could Lose Custody of Fourteen-Year-Old Over This

Mon Nov 7 3:33 AM by garbage videos in Pregnancy & Parenting

It is wrong to lock horses in cages and breed them as if they are slaves.
I sincerely hope that you aren't condoning slavery with that implication that it isn't wrong to keep humans in cages and force them to "breed". It's probably just an unfortunate word choice.
I said it is wrong to put horses in cages and breed them as slaves. So I don't know how you read things. Frankly you are irritating me because I shouldn't have to explain how I said 2+2=4 when you are accusing me of saying 2+2=5. In this age people should have mastered how to read clearly and I shouldn't have to micromanage my text and clear what I have already layed out clearly for you.

To be fair, if the girl is a Female to Male transsexual, her hormones are not so important, at an old age Male hormones will mutate her body and have the same effect. But with boy's its more tragic and serious. Boys who want to be girls, must stop their toxic T at an early age, or else their face will be permanently ugly and bony


Cry it out vs. Attachment

Mon Sep 26 12:12 AM by lyra211 in Pregnancy & Parenting

We sort of went middle-of-the-road. In the beginning, we had the sidecar cosleeper, and that worked great. Baby woke up a lot at night because he was a newborn, but I could pick him up, feed him, and put him back down without getting out of bed. He seemed to pretty much only be waking up if he was hungry, and settled pretty well after that, so all was good with the world (yes, there were nights when we'd have to get up and bounce on the yoga ball for a while, but we never had the horrific newborn nights that we seem to hear about where he was inconsolable at 2am). He started sleeping longer stretches and was sleeping one 8-9 hour stretch per night by the time he was two months old.

Around 3 months as he started getting more sensitive to noise, our nighttime rustlings would wake him up -- and if it wasn't my husband or me rustling it was the dog, who also sleeps in our room. It got to the point where I was so worried about someone waking him up that if I heard anyone moving in the night I'd instantly be alert and ready to murder someone if the baby woke up, and then even if the baby didn't wake up I was all keyed up and would have trouble falling back asleep. So for about a month, I moved myself to the floor of the baby's room. He transitioned easily into the crib, but I slept on the floor of his room every night and fed him when he woke up hungry.


learning to use a toilet

Sun Sep 11 2:33 PM by Angelica in Pregnancy & Parenting

My statement was meant to indicate that I'm not finished with my thoughts on this topic, rather than to create drama.

I believe parents in this world universally make a big mistake when it comes time to start thinking about their children using the toilet. Kids feel forced to do it, and this breeds resentment and damages their self-esteem. Having the father (the mother is needed in the battle against the patriarchy) stay home with the children and homeschool them while they haven't yet decided to train themselves is the way to avoid humiliation by their more-repressed peers.

I would also like to point out that limiting elimination to the toilet at any age creates situations where the person's health is compromised due to the lack of availability of a bathroom. In these situations, I strongly advise parents to let their children wear diapers no matter their age. Retention can lead to kidney stones, intestinal damage, urinary tract infections and harmful bacteria and toxins in the bloodstream.


How to Announce Baby #4?

Thu Sep 8 5:00 AM by Carol Palmer in Pregnancy & Parenting

FB pic is the best idea. All your friends and relatives can definitely post in comments or expressions . Consider yourself lucky to have many children. They are a blessing from God


development balalnce

Wed Dec 7 8:16 PM by Nachos in Pregnancy & Parenting

I don't have a baby of my own, but my friend's baby is super talkative quite early and good at fine motor control and feeds herself lots, but didn't learn to crawl until recently and only now has shown interest in walking, but not solo. She's a bit older than a year. But she's happy and does learn things, just not all at the same rates.


kids' obsessions

Sat Oct 15 8:08 PM by melsbells in Pregnancy & Parenting

I could see saunas becoming an obsession for a number of very social reasons as well, depending on your family's sauna practices. I honestly can't think of any common themes or rituals shared by all branches of my U.S. family, other than like eating together, but that seems too banal(/essential for survival) to really become an obsession. My Finnish family, on the other hand, all sauna as a social ritual. Whether or not you allow your kid in saunas yet, if there's a lot of exposure to the ritual, they could probably pick up on the social importance. It might make sense that kids are probably wired to pick up on things that the adults in their life think are important (**not a child psychologist**).
<...> I know I was super into the instant evaporation of water and associated *hissssss* the first time I was in a sauna at like age seven.
This is an excellent point. And although I know they exist, I haven't encountered any Finns who don't like sauna. There are a lot of steps to it. The kid gets to help their grandfather build the fire when we're together, knows that wood burning saunas are better than electric saunas, and absolutely loves the sound of the water hitting the hot stones. I can't imitate the sound as well as the kid does.


bringing children up naturist

Sat Sep 24 1:18 AM by filmmakingally in Pregnancy & Parenting

It's about teaching children to make love so that they do it themselves. Love has no age or genetic requirement. It's healthy for young siblings to make love, and it's unhealthy if they don't. Sexual repression of children fucks them up as adults. Because the parents are secretive about it, children get the idea that it's bad, which starts the process of sexual repression.

Gross. Yuck. Eww. I've run out of ways to express how disgusted I am with what you've said here. Ewwwwwww!!!!!!!

No, siblings should not make love. It is in our genetic interest that we don't do this. Ever. This is a cultural universal.


Middle grade / Beginning Chapter Books

Fri Sep 9 8:01 PM by melsbells in Pregnancy & Parenting

I think a big driver in getting them to read is to find stories that they like.
Definitely this. I once tutored a kid who had been held back twice in elementary school and was still a couple grade levels behind on reading skills. He was given a book from the Captain Underpants series because it was supposed to be at his reading level but he thought it was utterly stupid. I don't think we ever found books that both matched his reading level and maturity level, but once we started reading books better suited to his interests, it didn't matter that they were more difficult.

One of my cousins kids read the Warriors series and was really into it. She was bulllied in school, but I don't think it was instigated by her reading choices.

I don't know any recent books for this age group but I've heard great things about the Adventure Time comics.


Carriers vs Ring Sling

Mon Sep 5 8:59 PM by melsbells in Pregnancy & Parenting

^That's funny because the bjorn carrier is the one I was given that I didn't like. I think that just re-emphasizes that the same thing isn't going to work the same for everyone.


protective restrictions for children

Tue Dec 6 10:08 PM by melsbells in Pregnancy & Parenting

The Wolfpack, a documentary about six bright teenage brothers have spent their entire lives locked away from society in a manhattan housing project. all they know of the outside is gleaned from the movies they watch obsessively (and recreate meticulously). yet as adolescence looms, they dream of escape, ever more urgently, into the beckoning world. The film is coming from the bias that the parents have wronged their children. We're told that in the past they have left the apartment, only as a group, and up to eight times a year. One year they didn't get out at all. It's unclear what the objective of these outings were. The film leaves a lot unanswered. We know they are homeschooled by their mother, who's a certified teacher, but what the homeschooling looked like is never examined. I can't help but think that these kids all around really healthy, charming, affectionate, considerate, welcoming, really only positive adjectives come to mind.


Sleep Training for Parents and Infants

Sat Oct 1 9:34 PM by antfancier in Pregnancy & Parenting

Thank you! I'm currently stuck under 20lbs of sleeping baby because all day time naps have to be in my arms or they don't happen.


Don't give your kids antidepressants.

Thu Sep 15 9:13 PM by Nachos in Pregnancy & Parenting

Mental health issues will never start to hurt, therefore no preemptive treatment is needed.

Mental health issues hurt, take it from me. There are many psychosomatic disorders out there which affect your body even though the real problem is in your mind. But to get better, you HAVE to treat both. Pre-emptive treatment also can stop some disorders from becoming too bad. And yes, sometimes drugs can be very very helpful.

I don't think you know what you're talking about and all this "I know because of divine intuition" bullshit is starting to piss me off. if you ask others for sources, be kind enough to provide some yourself.

If this thread continues to be shit-slinging, I will lock it.


Denial Trends?

Thu Jul 21 7:24 PM by SameMom in Pregnancy & Parenting

Sorry, if I was not able to mention other details. Actually, I have a (US) medicare insurance. And I am particularly referring to this denial management software which help clients with their claims. Thanks for your reply. :)