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% -% -% 2.9% 9.9% 17.8% 26.6%
Sunday December 11th, 2016 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Monday December 12th, 2016 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Tuesday December 13th, 2016 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Wednesday December 14th, 2016 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Thursday December 15th, 2016 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Friday December 16th, 2016 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Saturday December 17th, 2016 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Sunday December 18th, 2016 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Monday December 19th, 2016 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Tuesday December 20th, 2016 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Wednesday December 21st, 2016 40W, 1D 3.97% 53.98% -% -% 8.6% 25.1% 40.4% 54%
Thursday December 22nd, 2016 40W, 2D 3.91% 57.93% -% -% 9.3% 26.7% 42.5% 56.2%
Friday December 23rd, 2016 40W, 3D 3.81% 61.79% -% -% 10% 28.2% 44.5% 58.5%
Saturday December 24th, 2016 40W, 4D 3.68% 65.54% -% -% 10.7% 29.8% 46.6% 60.6%
Sunday December 25th, 2016 40W, 5D 3.52% 69.15% -% -% 11.4% 31.3% 48.6% 62.7%
Monday December 26th, 2016 40W, 6D 3.33% 72.57% -% -% 12.1% 32.9% 50.5% 64.7%
Tuesday December 27th, 2016 41W, 0D 3.12% 75.8% -% -% 12.9% 34.4% 52.4% 66.6%
Wednesday December 28th, 2016 41W, 1D 2.9% 78.81% -% -% 13.7% 36% 54.3% 68.5%
Thursday December 29th, 2016 41W, 2D 2.66% 81.59% -% -% 14.4% 37.5% 56.1% 70.2%
Friday December 30th, 2016 41W, 3D 2.42% 84.13% -% -% 15.2% 39% 57.9% 71.9%
Saturday December 31st, 2016 41W, 4D 2.18% 86.43% -% -% 16.1% 40.5% 59.6% 73.5%
Sunday January 1st, 2017 41W, 5D 1.94% 88.49% -% -% 16.9% 42% 61.3% 75.1%
Monday January 2nd, 2017 41W, 6D 1.71% 90.32% -% -% 17.7% 43.4% 62.9% 76.4%
Tuesday January 3rd, 2017 42W, 0D 1.5% 91.92% -% -% 18.6% 44.8% 64.5% 77.8%
Wednesday January 4th, 2017 42W, 1D 1.3% 93.32% -% -% 19.5% 46.3% 65.9% 79.2%
Thursday January 5th, 2017 42W, 2D 1.11% 94.52% -% -% 20.3% 47.6% 67.3% 80.5%
Friday January 6th, 2017 42W, 3D 0.94% 95.54% -% -% 21.1% 48.9% 68.8% 81.6%
Saturday January 7th, 2017 42W, 4D 0.79% 96.41% -% -% 22% 50.1% 70.2% 82.7%
Sunday January 8th, 2017 42W, 5D 0.66% 97.13% -% -% 23% 51.6% 71.4% 83.6%
Monday January 9th, 2017 42W, 6D 0.54% 97.72% -% -% 23.7% 53.1% 72.8% 84.6%
Tuesday January 10th, 2017 43W, 0D 0.44% 98.21% -% -% 24.6% 54.2% 73.7% 85.5%
Wednesday January 11th, 2017 43W, 1D 0.35% 98.61% -% -% 25.2% 55.4% 74.8% 86.3%
Thursday January 12th, 2017 43W, 2D 0.28% 98.93% -% -% 26.2% 56.1% 75.7% 87.9%
Friday January 13th, 2017 43W, 3D 0.22% 99.18% -% -% 26.8% 57.3% 76.8% -%
Saturday January 14th, 2017 43W, 4D 0.18% 99.38% -% -% 29% 58.1% 79% -%
Sunday January 15th, 2017 43W, 5D 0.14% 99.53% -% -% 29.8% 59.6% -% -%
Monday January 16th, 2017 43W, 6D 0.1% 99.65% -% -% 28.6% 62.9% -% -%
Tuesday January 17th, 2017 44W, 0D 0.08% 99.74% -% -% 30.8% -% -% -%
Wednesday January 18th, 2017 44W, 1D 0.06% 99.81% -% -% 31.6% -% -% -%
Thursday January 19th, 2017 44W, 2D 0.04% 99.87% -% -% 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.

stuffed animals

Tue Feb 21 9:51 PM by melsbells in Pregnancy & Parenting

I wanted to get our kid a stuffed animal before they were born. I was trying to assign some sort of personality to the kid by thinking up how to make an armadillo or something. Spouse convinced me to wait because we would inevitably get stuffed animals. There are far too many and they're almost all polyester crap that feels gross and sticky on my hands, even when new. For a while there was just one that the kid wanted to take everywhere, then two. It had gotten bad enough that I have had to say goodnight to eight different stuffed toys plus the blanket called "towel". Luckily after a trip away with only one, we have resisted the growing bed accumulation, though there are currently three.


Activities for 1-3 yo's

Sat Jan 14 7:07 PM by antfancier in Pregnancy & Parenting

I find theimaginationtree.com has lots of inspiring ideas. Some look like they take quite a bit of prep, but if you're doing it for a whole class then it might be worth it. You can sort activities by age as well so it's easier to search.


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.


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.


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.


What did I just say?

Tue Feb 21 3:00 PM by Sonic# in Pregnancy & Parenting

"Don't eat the catfood" - to a friend's kid.


tactile stuff

Wed Jan 4 6:14 AM by Neko in Pregnancy & Parenting

All the pliable/crafty stuff I can think of has been mentioned. ETA: I lied. Bread dough!

But if generally tactile surfaces also apply, mermaid sequin pillows are comforting. It was one of my impulse buys at a department store about a month ago. I couldn't stop petting the display. The sequined side seemed like it wouldn't be comfortable to rest on but it hasn't been an issue. My stepdad really likes them so I got him one for giftmas and he said it helps distract him when chronic pain keeps him awake at night. https://www.etsy.com/listing/470423508/ ... _active_40

I haven't field tested them on my nieces and nephews yet. That could be fun.


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.


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.


New parent help/suggestions

Sat Jan 14 10:07 PM by antfancier in Pregnancy & Parenting

I agree with everything lyra211 said and will add a few more.

Things you don't need:
Anything soft, fluffy or furry. My baby couldn't care less about minky blankets and soft toys. Plus they seem more gross to clean when they get covered in bodily fluids.
Clothes that look like adult clothes. It's so difficult to squeeze baby thighs into miniature corduroys or denim jeans which have no give to the fabric.
Baby washcloths. Babies make a disproportionate amount of mess so you need adult size washcloths to clean them up.

Things that were super useful:
A folding changing mat. I have a SkipHop one which has enough storage for wipes and diapers, which was all I needed to carry with me when I had a newborn. Now that he's bigger, I appreciate the larger size of the mat because the one that came with my diaper bag is way too small.
Balls. They were the first thing he played with and still his favourite toys. At the beginning he liked one made by Oball which was easy to pick up, and a soft fabric one which made a crinkly noise. Now he loves throwing a soft rubber ball and watching it bounce.


development balalnce

Fri Dec 16 5:02 PM by rinn in Pregnancy & Parenting

I was proficient in fine/gross motor skills and cognitive development for my age, but I was further behind in speech/language development and social/emotional development. I caught up in them perhaps by ages 5-7, with vestiges of social issues lasting longer (like my temper). There was nothing inherently bad about being a bit off in timing, though in my case my imbalance was severe enough that I did need professional help from a speech pathologist.

....New social situations make me feel somewhat awkward, but I've also learned that many other people feel the same way about novel contexts, so I think I'm with the curve there.

geez, are you my twin, sonic? XD

I grew up with definite lag in speech/language development. I had a speech pathologist in elementary school work on my -L-'s, -r-'s and -th-'s; and when I essentially "graduated" from it I was taken out of the IEP program. my mom and I now see that being a mistake. middle school went decently, but I struggled in language arts; and by the time I went into high school I was struggling in my history/English humanities course and Algebra. I struggled in English classes because of my inability to express myself through language clearly, and I struggled in algebra because I couldn't follow a thing my teacher was saying (we had someone tutor me who literally asked why she was tutoring me because I grasped the concepts five minutes after her explaining it).


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


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.