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 September 5th, 2017.

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

housemates + newborn = ?

Wed Jul 18 6:31 PM by octarineoboe in Pregnancy & Parenting

HOLY BURIED LEDE BATMAN



I admit I haven’t been around here a ton lately but I didn’t know babySonic had arrived! Congrats!!!!



Alas I don’t have any actual advice. My college besties (a married couple) and I fantasize about sharing a house, and they are actively trying to have kids, so we talked about that possibility a little bit, but right now we live in different cities and they don’t have a kid yet so it’s all speculation. But I think it could probably work - as the prospective non-parent I would want to make sure I had my own kid-free space in the house and we were really clear about responsibilities ahead of time, eg, I’m a roommate not an all-purpose babysitter, how will this affect the split of other housework, etc.


My Ectopic Pregnancy

Tue Jan 23 8:47 PM by rowan in Pregnancy & Parenting

FYI we have a general culture in the pregnancy forum here about sharing similar stories as a way to offer support, and also about giving any medical knowledge that we've come across, since pregnancy is generally not talked about as much as it should be and you find information in random places. Since you haven't been around until now you probably didn't know that, and mels' post is well in line with forum guidelines and norms. Please don't go all mod martyr on us now that you're only just back. This is me as a friend speaking here, not with my modhat on.



I'm sorry for your loss. Ectopic pregnancies are scary, and I would like to go punch that first doctor in the face for you.



PPD is awful too. :( I hope you can get through it.


gender recognition

Thu Nov 2 1:03 PM by Nech in Pregnancy & Parenting


You can continue discussing with him the difference of a boy and a girl. Have him socialize too with the same gender. There's nothing wrong if you have go with opposite sex as long as he understands what/who he is.


So do you feel hanging out with the opposite gender at a young age can confuse a person's gender identity?


leftist parenting and gender [split from gender recognition]

Sat Sep 23 11:52 AM by Unvoiced_Apollo in Pregnancy & Parenting


gender recognition.">



If a boy who has a penis asks if he's a boy and you don't just say yes, then that's straight up lunacy.



What he decides to do with that boyhood or how he dresses is up to him. But if you're born with a penis you're a boy.



Making it airy fairy when, statistically, scientifically, less than 1% of 1% of children born have true gender dysphoria, is immoral and wrong. It's also a sign of our troubled times.


This is just my anecdotal experience but...



I have experienced bullying based on simply engaging in normal children's play with girls. Insults were attacks on both me and the girls. But I NEVER questioned my gender as a male. So if a child asks me if he's a boy and was identified biologically as one, I am going to question what influences are on the child before I answer.


Postpartum issues: things that can go wrong after

Wed Aug 9 5:24 PM by rowan in Pregnancy & Parenting

ugh that totes doesn't just happen during c-section. I had a friend who found out when she was having (other) surgery years later and they stitched her up since "they were in there anyway". Honestly I think I also have it but it doesn't cause problems *most* of the time (sometimes stabby pain but no one takes it seriously so idk).


Unplanned, polyamorous pregnancy situation

Sun Apr 29 12:18 PM by metawidget in Pregnancy & Parenting

I'm glad you have been communicating and working things out. I wish you lots of health and love as you wrote the next chapter of this story.


I might be pregnant...

Fri Jan 5 3:16 AM by Aum in Pregnancy & Parenting


Aum, my partner and I were just discussing this. He was surprised by my taking the hard line that stopping BC or poking holes in condoms or something like that is rape, making the woman a rapist. Which should result in jail time, so she should lose custody, which should go to the father and now he has the choice of keeping the baby or putting them up for adoption.

It's unfortunate that you can't prove such a thing, but hopefully if it was actually taken seriously women would be less likely to do it because it would at least be explicitly called rape.


I understand how the justice system and the family courts would look at it. They see it as the man's sperm made it to the egg so somehow he wasn't protecting himself, he made the choice, yada yada. There's no way to prove that the woman was manipulative, withdrew BC, or "poked holes in the condom" (I think that's unheard of, but anyway).


When do you outsource parenting?

Sat Oct 14 7:47 PM by rowan in Pregnancy & Parenting

yeah I do a ton of supplemental history... :(


It might be time for a baby.

Sat Sep 16 1:59 PM by Sonic# in Pregnancy & Parenting

I got curious on the question of single parent families. Definitely, I think financial stability or having some sort of support network (family, friends) is better than not having it.



I found this article ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4886836/ ). The article does point out that several factors adjust child adjustment, like finances and parental stress. Merely being a single parent? Not a factor:
The findings suggest that solo motherhood, in itself, does not result in psychological problems for children.

The lit review at the beginning of the article adds some specificity here. What seems hard on kids is not single parenthood itself; it's often the divorce that results in a single parent being involved. These studies have consistently shown that children whose parents divorce are more likely to show emotional and behavioral problems than are children in intact families (Amato, 2000, 2001, 2005; Coleman & Glenn, 2009; Hetherington & Stanley-Hagan, 1999; Pryor & Rodgers, 2001). However, the children’s difficulties appear to be largely associated with aspects of the divorce, rather than single-parenthood, in itself. Then there are people who become single parents, but not by choice. That's also rough, often because these parents lack the financial stability and stability to do well. So the article is really looking at single parents by choice. They can raise children as well as two-parent households.


How to deal with opinionated toddlers (or babies or kids)

Tue Aug 1 1:57 AM by rowan in Pregnancy & Parenting

Ooof. My kid is very social, needs to be around someone all the time. It's ... challenging, as you've found. It does get better as they gain their own interests. But it took a long time to get past clingy.



Not having read your post, but just the heading, my response was "wine." But after reading your post, I thought "wine."

Yes. After bedtime.



Also, honestly the only way we made it through was we would take turns being the center of focus. We still do this, divide and conquer (and she's only one kid, hell). Also, I know people are like really limit screen time BUT if you really need to get something done one episode of e.g. Daniel Tiger or Paw Patrol or whatever isn't gonna be too bad. I think DarkOne has some good ideas too.



Good luck.


posting pictures of kids and privacy

Wed Apr 25 7:29 AM by juliabonl17 in Pregnancy & Parenting

Usually, we don't share photos of our children in social media. Sometimes I can send some photos to close friends. I keep my personal life in quiet. Share with family only.


I had my 2nd baby!!!!

Wed Jan 3 8:21 PM by MFS in Pregnancy & Parenting

OMG BABY!



I am still dealing with the fact that your 11 year old is an actual 11 year old.


on being semi-pregnant

Tue Oct 3 7:18 PM by geldofc in Pregnancy & Parenting

congratulations!! i've never been pregnant but i'm jealous. i'm having baby fever lately.


Clock-Ticking

Wed Sep 13 6:58 PM by geldofc in Pregnancy & Parenting

my clock started ticking in my 20s and i would love a child at 30 now but i want to live how i want for a few more years, and have my career established. i don't see parenthood for another 5 years.



egg freezing seems like a good option esp if you have extra time and money.


bad reasons for having a baby

Tue Aug 1 1:47 AM by rowan in Pregnancy & Parenting

but I take them to restaurants so I know they end up hating 90% of the things they ask for.
:lol:



- kid would like a sibling

- maybe people are right about end of life stuff



That's about it. I hated being pregnant, the last time I was pregnant the hormones were... really awful. Plus kid is now pretty big so another one would be weird and we gave away all our stuff. ;)