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

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.

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.

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: ( ... 1857885252) 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!

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).

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

Wed Jul 26 12:39 AM by antfancier in Pregnancy & Parenting

So I remember reading that some of you have offspring with 'strong' personalities. At our 15 month checkup, the pediatrician said "oh, he's very opinionated" and I was like "yeah, no fucking shit." But seriously, how do you handle it? All the advice seems to be that high need babies grow up to be great kids, but that does nothing to help me right now. In fact, it sounds like something you tell people so they'll continue to struggle through their current situation in the vague hope that it won't last forever.

Right now we're struggling with independent play. Actually he can play fine by himself if I'm in the room and not doing anything. But if I pay attention to something else, or actually try to leave the room, he gets mad and vocalizes his displeasure very loudly (no tears, more like a whining shout). Actually, he's been like this since he was he was born, but it's only now that I've realized it. I don't think it's separation anxiety (we have been through phases of that), but rather he just can't bear to miss out on something. He's really social, will hug total strangers and follow older kids (and animals) around the park. If he has attention from people, he couldn't care less where I am.

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 ..

Activities for 1-3 yo's

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

I find 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.

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.

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. ... _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.