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 25th, 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
Monday August 21st, 2017 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Tuesday August 22nd, 2017 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Wednesday August 23rd, 2017 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Thursday August 24th, 2017 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Friday August 25th, 2017 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Saturday August 26th, 2017 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Sunday August 27th, 2017 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Monday August 28th, 2017 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Tuesday August 29th, 2017 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Wednesday August 30th, 2017 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Thursday August 31st, 2017 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Friday September 1st, 2017 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Saturday September 2nd, 2017 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Sunday September 3rd, 2017 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Monday September 4th, 2017 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Tuesday September 5th, 2017 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Wednesday September 6th, 2017 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Thursday September 7th, 2017 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Friday September 8th, 2017 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Saturday September 9th, 2017 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Sunday September 10th, 2017 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Monday September 11th, 2017 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Tuesday September 12th, 2017 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Wednesday September 13th, 2017 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Thursday September 14th, 2017 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Friday September 15th, 2017 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Saturday September 16th, 2017 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Sunday September 17th, 2017 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Monday September 18th, 2017 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Tuesday September 19th, 2017 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Wednesday September 20th, 2017 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Thursday September 21st, 2017 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Friday September 22nd, 2017 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Saturday September 23rd, 2017 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Sunday September 24th, 2017 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Monday September 25th, 2017 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Tuesday September 26th, 2017 40W, 1D 3.97% 53.98% 7.9% 8% 8.6% 25.1% 40.4% 54%
Wednesday September 27th, 2017 40W, 2D 3.91% 57.93% 7.8% 15.9% 9.3% 26.7% 42.5% 56.2%
Thursday September 28th, 2017 40W, 3D 3.81% 61.79% 7.6% 23.6% 10% 28.2% 44.5% 58.5%
Friday September 29th, 2017 40W, 4D 3.68% 65.54% 7.4% 31.1% 10.7% 29.8% 46.6% 60.6%
Saturday September 30th, 2017 40W, 5D 3.52% 69.15% 7% 38.3% 11.4% 31.3% 48.6% 62.7%
Sunday October 1st, 2017 40W, 6D 3.33% 72.57% 6.7% 45.1% 12.1% 32.9% 50.5% 64.7%
Monday October 2nd, 2017 41W, 0D 3.12% 75.8% 6.2% 51.6% 12.9% 34.4% 52.4% 66.6%
Tuesday October 3rd, 2017 41W, 1D 2.9% 78.81% 5.8% 57.6% 13.7% 36% 54.3% 68.5%
Wednesday October 4th, 2017 41W, 2D 2.66% 81.59% 5.3% 63.2% 14.4% 37.5% 56.1% 70.2%
Thursday October 5th, 2017 41W, 3D 2.42% 84.13% 4.8% 68.3% 15.2% 39% 57.9% 71.9%
Friday October 6th, 2017 41W, 4D 2.18% 86.43% 4.4% 72.9% 16.1% 40.5% 59.6% 73.5%
Saturday October 7th, 2017 41W, 5D 1.94% 88.49% 3.9% 77% 16.9% 42% 61.3% 75.1%
Sunday October 8th, 2017 41W, 6D 1.71% 90.32% 3.4% 80.6% 17.7% 43.4% 62.9% 76.4%
Monday October 9th, 2017 42W, 0D 1.5% 91.92% 3% 83.8% 18.6% 44.8% 64.5% 77.8%
Tuesday October 10th, 2017 42W, 1D 1.3% 93.32% 2.6% 86.6% 19.5% 46.3% 65.9% 79.2%
Wednesday October 11th, 2017 42W, 2D 1.11% 94.52% 2.2% 89% 20.3% 47.6% 67.3% 80.5%
Thursday October 12th, 2017 42W, 3D 0.94% 95.54% 1.9% 91.1% 21.1% 48.9% 68.8% 81.6%
Friday October 13th, 2017 42W, 4D 0.79% 96.41% 1.6% 92.8% 22% 50.1% 70.2% 82.7%
Saturday October 14th, 2017 42W, 5D 0.66% 97.13% 1.3% 94.3% 23% 51.6% 71.4% 83.6%
Sunday October 15th, 2017 42W, 6D 0.54% 97.72% 1.1% 95.4% 23.7% 53.1% 72.8% 84.6%
Monday October 16th, 2017 43W, 0D 0.44% 98.21% 0.9% 96.4% 24.6% 54.2% 73.7% 85.5%
Tuesday October 17th, 2017 43W, 1D 0.35% 98.61% 0.7% 97.2% 25.2% 55.4% 74.8% 86.3%
Wednesday October 18th, 2017 43W, 2D 0.28% 98.93% 0.6% 97.9% 26.2% 56.1% 75.7% 87.9%
Thursday October 19th, 2017 43W, 3D 0.22% 99.18% 0.4% 98.4% 26.8% 57.3% 76.8% -%
Friday October 20th, 2017 43W, 4D 0.18% 99.38% 0.4% 98.8% 29% 58.1% 79% -%
Saturday October 21st, 2017 43W, 5D 0.14% 99.53% 0.3% 99.1% 29.8% 59.6% -% -%
Sunday October 22nd, 2017 43W, 6D 0.1% 99.65% 0.2% 99.3% 28.6% 62.9% -% -%
Monday October 23rd, 2017 44W, 0D 0.08% 99.74% 0.2% 99.5% 30.8% -% -% -%
Tuesday October 24th, 2017 44W, 1D 0.06% 99.81% 0.1% 99.6% 31.6% -% -% -%
Wednesday October 25th, 2017 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 (

Charts are generated by flot.

More tools

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.

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.


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.

- 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. ;)

how do you travel?

Mon Jun 19 11:00 AM by DarkOne in Pregnancy & Parenting

We're traveling with a 2 yo and a 4yo this week. A 2 hr flight connecting to a 4 hr flight. I broke down and got tablets and headphones, now I just need to load them with movies/games. I'm packing treats and stickers and crayons and notepads. I'm almost positive I'll be carrying on a (very compactable) pillow, 'cause they don't give those out anymore on board. I'm banning toys that can roll several aisles fwd or back when inevitably dropped (besides the crayons). I was planning on gum for ascent/descent, but I think the suckers for the 2yo will be better. I'm so not looking forward to these flights. Maybe the kids will surprise me and be awesome. I'm not worried about the 4yo. But the 2yo...

Bilingual Toddler

Wed May 3 10:19 PM by Nachos in Pregnancy & Parenting

Bilingualism! This is something I know a lot about! My last job was to speak English to my class in a partial immersion school and the kids picked up English so fast but spoke back to me in German. We worked on saying different words in German and in English and it meaning the same thing and I read English books to them. They differentiated pretty well but most of them came from a mono-lingual family background.

I can still highly recommend this book: ( for bilingual children. Some very good advice in there.

Also, keep speaking English! Toddlers forget fast when a language is no longer present.

Yay bilingualism!

gender recognition

Tue Sep 19 11:05 AM by melsbells in Pregnancy & Parenting

MOD NOTE: This thread was split into this thread. I wanted to pull the resources responding to the question in the OP that were in posts split into the other thread.

Mels, I know Cordelia Fine's books on gender and neuroscience address little kids and the infleunces they receive at certain points. To my memory, her work was mainly demonstrative - hey, yes, kids are externally exposed to gender at very early points, and we can see kids beginning to internalize these ideas about gender.

Looking at Wikipedia, I know I've read one of the cited articles before and found it interesting (Martin, C. L. (1990). "Attitudes and Expectations about Children with Nontraditional and Traditional Gender Roles". Sex Roles. 22 (3-4): 151–66.) The gist is that understandings of gender begin to emerge by ages 2 or 3, and they continue to develop over the course of years, which includes some stigma (esp. for boys) when people step outside of understood roles. Then this article is more recent than that (2017), by the same author, and (based on my skim) seems to have pretty decent coverage in the articles it uses (

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).

Just Can't Let It Go

Wed Jul 26 1:18 AM by Taurwen in Pregnancy & Parenting

We didn't find out specifically because we didn't want a lot of pink stuff if it was a girl.

Somehow MIL has still given us a ton of pink clothing that she'll change him into everytime she comes over.

I hate pink.

Another baby stars

Thu Jun 15 6:54 AM by StarsInUrEye in Pregnancy & Parenting

Thanks for the congratulations and encouragement.

I had an appointment with the obgyn today. He seems to think I'm even farther along than he originally thought. I didn't have an ultrasound. He just went by the size of my uterus. It's well over my belly button now. He's sending me to a high risk Dr. Asap and then I'm suppost to see him again on the 29th. By then he said they will have a better idea as to how far along I actually am. So far the pregnancy is going well. I did have complications with my first one and went to a specialist but this time I'm being referred to one because I'm old lol. They automatically send women when they are 35 and older.

What did I just say?

Wed Mar 15 12:25 PM by mariareese in Pregnancy & Parenting

Looking to know about the system and biology :D hehe ..

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 ( ). 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.

Happiest Baby on the Block

Wed Jul 12 4:52 PM by antfancier in Pregnancy & Parenting

My mum gave me 'Your Baby and Child' by Penelope Leach, which is what she used when she had me. It covers from birth to five years. I read the first section about newborns in preparation. After having the baby, I realised I have zero time or brain power to do anything so I never got around to the rest of it. In general, I liked the book though. It's a simple overview and has nice color photos.

To all Moms: Where do you go for financial concerns?

Tue May 9 4:18 PM by rowan in Pregnancy & Parenting

My father in law does financial advising so we kind of have an in-house advisor? But seriously someone with expertise is great. There are various "how to do finances" through our local community ed, which I'd probably consider if I didn't already have someone to ask. Maybe something like that near you? Libraries also sometimes have programs.

Also I know you can do wills and stuff on your own but honestly I found it super useful to talk through it with a lawyer who does that. She thought of things we never would have. (hm really should revisit now that kid is older) It was a one time fee and not that bad.

We do most of our banking through a credit union. Have been happy with them. We refinanced our mortgage through them when we did that. I remember the big credit union bust ages ago, but there are lots more protections in place now and big banks can be pretty awful.

stuffed animals

Thu Feb 23 1:20 AM by antfancier in Pregnancy & Parenting

My brother's favorite stuffed animal was a thing we called 'gerbil'. I actually don't know what it was because we found it in the street (not sure what my mum was thinking in allowing him to pick it up, let alone keep it) and it had already lost an eye and was unidentifiable, but he became really attached to it. We almost missed a flight once because he dropped it in the airport and we had to go back to look for it.

Today for the first time my 11month old showed interest in a stuffed animal. Just before Christmas we received a box from Amazon with a giant bear inside. No gift wrap, no note. Just a bear the size of my child. It's been sat in his room and ignored completely, despite him exploring literally everything else that is in there. Then, out of the blue, he made a beeline for it and tried to pull its eyes out.