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, 2018.

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
Wednesday August 1st, 2018 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Thursday August 2nd, 2018 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Friday August 3rd, 2018 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Saturday August 4th, 2018 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Sunday August 5th, 2018 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Monday August 6th, 2018 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Tuesday August 7th, 2018 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Wednesday August 8th, 2018 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Thursday August 9th, 2018 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Friday August 10th, 2018 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Saturday August 11th, 2018 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Sunday August 12th, 2018 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Monday August 13th, 2018 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Tuesday August 14th, 2018 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Wednesday August 15th, 2018 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Thursday August 16th, 2018 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Friday August 17th, 2018 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Saturday August 18th, 2018 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Sunday August 19th, 2018 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Monday August 20th, 2018 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Tuesday August 21st, 2018 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Wednesday August 22nd, 2018 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Thursday August 23rd, 2018 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Friday August 24th, 2018 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Saturday August 25th, 2018 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Sunday August 26th, 2018 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Monday August 27th, 2018 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Tuesday August 28th, 2018 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Wednesday August 29th, 2018 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Thursday August 30th, 2018 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Friday August 31st, 2018 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Saturday September 1st, 2018 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Sunday September 2nd, 2018 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Monday September 3rd, 2018 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Tuesday September 4th, 2018 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Wednesday September 5th, 2018 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Thursday September 6th, 2018 40W, 1D 3.97% 53.98% -% -% 8.6% 25.1% 40.4% 54%
Friday September 7th, 2018 40W, 2D 3.91% 57.93% -% -% 9.3% 26.7% 42.5% 56.2%
Saturday September 8th, 2018 40W, 3D 3.81% 61.79% -% -% 10% 28.2% 44.5% 58.5%
Sunday September 9th, 2018 40W, 4D 3.68% 65.54% -% -% 10.7% 29.8% 46.6% 60.6%
Monday September 10th, 2018 40W, 5D 3.52% 69.15% -% -% 11.4% 31.3% 48.6% 62.7%
Tuesday September 11th, 2018 40W, 6D 3.33% 72.57% -% -% 12.1% 32.9% 50.5% 64.7%
Wednesday September 12th, 2018 41W, 0D 3.12% 75.8% -% -% 12.9% 34.4% 52.4% 66.6%
Thursday September 13th, 2018 41W, 1D 2.9% 78.81% -% -% 13.7% 36% 54.3% 68.5%
Friday September 14th, 2018 41W, 2D 2.66% 81.59% -% -% 14.4% 37.5% 56.1% 70.2%
Saturday September 15th, 2018 41W, 3D 2.42% 84.13% -% -% 15.2% 39% 57.9% 71.9%
Sunday September 16th, 2018 41W, 4D 2.18% 86.43% -% -% 16.1% 40.5% 59.6% 73.5%
Monday September 17th, 2018 41W, 5D 1.94% 88.49% -% -% 16.9% 42% 61.3% 75.1%
Tuesday September 18th, 2018 41W, 6D 1.71% 90.32% -% -% 17.7% 43.4% 62.9% 76.4%
Wednesday September 19th, 2018 42W, 0D 1.5% 91.92% -% -% 18.6% 44.8% 64.5% 77.8%
Thursday September 20th, 2018 42W, 1D 1.3% 93.32% -% -% 19.5% 46.3% 65.9% 79.2%
Friday September 21st, 2018 42W, 2D 1.11% 94.52% -% -% 20.3% 47.6% 67.3% 80.5%
Saturday September 22nd, 2018 42W, 3D 0.94% 95.54% -% -% 21.1% 48.9% 68.8% 81.6%
Sunday September 23rd, 2018 42W, 4D 0.79% 96.41% -% -% 22% 50.1% 70.2% 82.7%
Monday September 24th, 2018 42W, 5D 0.66% 97.13% -% -% 23% 51.6% 71.4% 83.6%
Tuesday September 25th, 2018 42W, 6D 0.54% 97.72% -% -% 23.7% 53.1% 72.8% 84.6%
Wednesday September 26th, 2018 43W, 0D 0.44% 98.21% -% -% 24.6% 54.2% 73.7% 85.5%
Thursday September 27th, 2018 43W, 1D 0.35% 98.61% -% -% 25.2% 55.4% 74.8% 86.3%
Friday September 28th, 2018 43W, 2D 0.28% 98.93% -% -% 26.2% 56.1% 75.7% 87.9%
Saturday September 29th, 2018 43W, 3D 0.22% 99.18% -% -% 26.8% 57.3% 76.8% -%
Sunday September 30th, 2018 43W, 4D 0.18% 99.38% -% -% 29% 58.1% 79% -%
Monday October 1st, 2018 43W, 5D 0.14% 99.53% -% -% 29.8% 59.6% -% -%
Tuesday October 2nd, 2018 43W, 6D 0.1% 99.65% -% -% 28.6% 62.9% -% -%
Wednesday October 3rd, 2018 44W, 0D 0.08% 99.74% -% -% 30.8% -% -% -%
Thursday October 4th, 2018 44W, 1D 0.06% 99.81% -% -% 31.6% -% -% -%
Friday October 5th, 2018 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.

kids' mail subscriptions

Sun Nov 11 12:47 PM by melsbells in Pregnancy & Parenting

Does anyone get a box or magazine subscription for their kid? Any you would recommend?



My mom had the idea of giving my kid Little Passports but they don't ship to Finland. Kiwico has a similar line that will come here, but there's still the concern about how well they're teaching about different cultures, how much does it other and ignore colonialism? Does it cross the line from appreciating world cultures into consuming cultures for entertainment?



I think the concept is good. My kid would really enjoy some kind of activity subscription and I thank the world based ones would make my mom feel more connected to her overseas grandchild, but maybe science or art based is safer.



Edited to fix links.


housemates + newborn = ?

Thu Aug 2 11:57 AM by melsbells in Pregnancy & Parenting

I live with my in-laws, and while there will certainly be a lot of differences from your situation, maybe there's enough similarities that my experience could be useful to you. I think the biggest thing is that everyone has their own space. Our house is sort of divided in two, so we can take the kid to our end during a tantrum. I think that distance helps, not just with in-laws not wanting to hear screaming, but as a sort of physical signal for the kid to calm down. We lived in an apartment when the kid was first born and our neighbors there probably heard more screaming/crying due to proximity.



My father-in-law spends a lot of time with the kid, mostly by choice. I sometimes wish we had more of a schedule, because at the moment, naps and bedtime are the only semi-guaranteed breaks for anyone. My spouse and father-in-law both work from home free-lance, so they don't actually have a schedule for when they need to be left alone, but at least my father-in-law has more warning with jobs scheduled out in advance.


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.


How important is school?

Fri Oct 26 11:31 AM by Pikachu in Pregnancy & Parenting

Worse than useless. School is psychologically damaging. https://www.telegraph.co.uk/education/educationopinion/12025711/Schools-largely-to-blame-for-rising-mental-health-issues.html



If you can show up on time, work with other people, follow orders, learn and repeat basic routines, you're fit for most work.


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 the 2nd pregnancy / labor was different from the first

Thu Sep 27 8:20 PM by antfancier in Pregnancy & Parenting

I haven’t been around for a long time, but I’m back and pregnant again. Only 6 weeks, so I can’t really comment much, but this time around it has been easier so far. Not easy, but considering I’m working and have a 2.5yr old (neither of which applied to last pregnancy), I thought I’d feel much worse. I still have ALL the symptoms and they all started at 3 weeks, just like last time (and the same as a chemical pregnancy I had too) but they don’t seem to be as constant as before. I’m really glad about that! The only thing that’s worse is back ache, ligament pain, general body aches. I assume it’s because my body is already exhausted and broken from my toddler.


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.