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, 2015.

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
Sunday November 15th, 2015 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Monday November 16th, 2015 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Tuesday November 17th, 2015 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Wednesday November 18th, 2015 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Thursday November 19th, 2015 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Friday November 20th, 2015 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Saturday November 21st, 2015 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Sunday November 22nd, 2015 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Monday November 23rd, 2015 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Tuesday November 24th, 2015 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Wednesday November 25th, 2015 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Thursday November 26th, 2015 36W, 4D 0.22% 0.82% 0.2% 0.2% 0.2% 1% 2.1% 3.7%
Friday November 27th, 2015 36W, 5D 0.28% 1.07% 0.3% 0.5% 0.3% 1.2% 2.5% 4.5%
Saturday November 28th, 2015 36W, 6D 0.35% 1.39% 0.4% 0.8% 0.4% 1.5% 3.1% 5.4%
Sunday November 29th, 2015 37W, 0D 0.44% 1.79% 0.4% 1.2% 0.4% 1.8% 3.8% 6.4%
Monday November 30th, 2015 37W, 1D 0.54% 2.28% 0.5% 1.7% 0.6% 2.2% 4.5% 7.6%
Tuesday December 1st, 2015 37W, 2D 0.66% 2.87% 0.7% 2.3% 0.7% 2.7% 5.4% 8.9%
Wednesday December 2nd, 2015 37W, 3D 0.79% 3.59% 0.8% 3% 0.8% 3.2% 6.3% 10.4%
Thursday December 3rd, 2015 37W, 4D 0.94% 4.46% 0.9% 3.9% 1% 3.8% 7.4% 11.9%
Friday December 4th, 2015 37W, 5D 1.11% 5.48% 1.1% 4.9% 1.2% 4.4% 8.6% 13.7%
Saturday December 5th, 2015 37W, 6D 1.3% 6.68% 1.3% 6.1% 1.4% 5.2% 9.8% 15.5%
Sunday December 6th, 2015 38W, 0D 1.5% 8.08% 1.5% 7.5% 1.6% 6% 11.2% 17.5%
Monday December 7th, 2015 38W, 1D 1.71% 9.68% 1.7% 9.1% 1.9% 6.9% 12.7% 19.7%
Tuesday December 8th, 2015 38W, 2D 1.94% 11.51% 2% 11% 2.2% 7.8% 14.3% 21.9%
Wednesday December 9th, 2015 38W, 3D 2.18% 13.57% 2.2% 13% 2.5% 8.8% 16% 24.2%
Thursday December 10th, 2015 38W, 4D 2.42% 15.87% 2.4% 15.3% 2.9% 9.9% 17.8% 26.6%
Friday December 11th, 2015 38W, 5D 2.66% 18.41% 2.7% 17.9% 3.3% 11.1% 19.7% 29%
Saturday December 12th, 2015 38W, 6D 2.9% 21.19% 2.9% 20.7% 3.7% 12.3% 21.6% 31.5%
Sunday December 13th, 2015 39W, 0D 3.12% 24.2% 3.1% 23.7% 4.1% 13.5% 23.6% 34%
Monday December 14th, 2015 39W, 1D 3.33% 27.43% 3.4% 27% 4.6% 14.9% 25.6% 36.6%
Tuesday December 15th, 2015 39W, 2D 3.52% 30.85% 3.5% 30.4% 5.1% 16.2% 27.7% 39.2%
Wednesday December 16th, 2015 39W, 3D 3.68% 34.46% 3.7% 34.1% 5.6% 17.6% 29.8% 41.7%
Thursday December 17th, 2015 39W, 4D 3.81% 38.21% 3.8% 37.8% 6.2% 19.1% 31.9% 44.2%
Friday December 18th, 2015 39W, 5D 3.91% 42.07% 3.9% 41.7% 6.7% 20.6% 34% 46.7%
Saturday December 19th, 2015 39W, 6D 3.97% 46.02% 4% 45.7% 7.4% 22.1% 36.2% 49.2%
Sunday December 20th, 2015 40W, 0D 3.99% 50% 4% 49.7% 8% 23.6% 38.3% 51.6%
Monday December 21st, 2015 40W, 1D 3.97% 53.98% 4% 53.7% 8.6% 25.1% 40.4% 54%
Tuesday December 22nd, 2015 40W, 2D 3.91% 57.93% 3.9% 57.7% 9.3% 26.7% 42.5% 56.2%
Wednesday December 23rd, 2015 40W, 3D 3.81% 61.79% 3.8% 61.6% 10% 28.2% 44.5% 58.5%
Thursday December 24th, 2015 40W, 4D 3.68% 65.54% 3.7% 65.3% 10.7% 29.8% 46.6% 60.6%
Friday December 25th, 2015 40W, 5D 3.52% 69.15% 3.5% 69% 11.4% 31.3% 48.6% 62.7%
Saturday December 26th, 2015 40W, 6D 3.33% 72.57% 3.4% 72.4% 12.1% 32.9% 50.5% 64.7%
Sunday December 27th, 2015 41W, 0D 3.12% 75.8% 3.1% 75.6% 12.9% 34.4% 52.4% 66.6%
Monday December 28th, 2015 41W, 1D 2.9% 78.81% 2.9% 78.7% 13.7% 36% 54.3% 68.5%
Tuesday December 29th, 2015 41W, 2D 2.66% 81.59% 2.7% 81.5% 14.4% 37.5% 56.1% 70.2%
Wednesday December 30th, 2015 41W, 3D 2.42% 84.13% 2.4% 84% 15.2% 39% 57.9% 71.9%
Thursday December 31st, 2015 41W, 4D 2.18% 86.43% 2.2% 86.3% 16.1% 40.5% 59.6% 73.5%
Friday January 1st, 2016 41W, 5D 1.94% 88.49% 2% 88.4% 16.9% 42% 61.3% 75.1%
Saturday January 2nd, 2016 41W, 6D 1.71% 90.32% 1.7% 90.3% 17.7% 43.4% 62.9% 76.4%
Sunday January 3rd, 2016 42W, 0D 1.5% 91.92% 1.5% 91.9% 18.6% 44.8% 64.5% 77.8%
Monday January 4th, 2016 42W, 1D 1.3% 93.32% 1.3% 93.3% 19.5% 46.3% 65.9% 79.2%
Tuesday January 5th, 2016 42W, 2D 1.11% 94.52% 1.1% 94.5% 20.3% 47.6% 67.3% 80.5%
Wednesday January 6th, 2016 42W, 3D 0.94% 95.54% 0.9% 95.5% 21.1% 48.9% 68.8% 81.6%
Thursday January 7th, 2016 42W, 4D 0.79% 96.41% 0.8% 96.4% 22% 50.1% 70.2% 82.7%
Friday January 8th, 2016 42W, 5D 0.66% 97.13% 0.7% 97.1% 23% 51.6% 71.4% 83.6%
Saturday January 9th, 2016 42W, 6D 0.54% 97.72% 0.5% 97.7% 23.7% 53.1% 72.8% 84.6%
Sunday January 10th, 2016 43W, 0D 0.44% 98.21% 0.4% 98.2% 24.6% 54.2% 73.7% 85.5%
Monday January 11th, 2016 43W, 1D 0.35% 98.61% 0.4% 98.6% 25.2% 55.4% 74.8% 86.3%
Tuesday January 12th, 2016 43W, 2D 0.28% 98.93% 0.3% 98.9% 26.2% 56.1% 75.7% 87.9%
Wednesday January 13th, 2016 43W, 3D 0.22% 99.18% 0.2% 99.2% 26.8% 57.3% 76.8% -%
Thursday January 14th, 2016 43W, 4D 0.18% 99.38% 0.2% 99.4% 29% 58.1% 79% -%
Friday January 15th, 2016 43W, 5D 0.14% 99.53% 0.1% 99.5% 29.8% 59.6% -% -%
Saturday January 16th, 2016 43W, 6D 0.1% 99.65% 0.1% 99.6% 28.6% 62.9% -% -%
Sunday January 17th, 2016 44W, 0D 0.08% 99.74% 0.1% 99.7% 30.8% -% -% -%
Monday January 18th, 2016 44W, 1D 0.06% 99.81% 0.1% 99.8% 31.6% -% -% -%
Tuesday January 19th, 2016 44W, 2D 0.04% 99.87% 0% 99.9% 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.

holiday shopping lists - kids/babies edition!

Wed Nov 25 11:20 AM by iamthegate in Pregnancy & Parenting

I know that for my niece, who has 3 pairs of grandparents and was the first grandkid of all of those, the parents put down a rule that every pair of grandparents could only gift one or two gifts, so she wouldn't get completely spoiled with gifts. The first year or two when they hadn't, stuff got a bit overboard (which was especially sad for my brother, who is just 4 years older than she is, and it's hard when someone else gets SO MUCH MORE gifts than he did).

I like buying books for kids. Even for very young ones, there are awesome books that can be read to them. Sadly, giving advice is hard, since most children's books I know are Dutch, and might not be translated.

Childbirth/infant cpr/baby care classes

Mon Nov 2 11:25 PM by antfancier in Pregnancy & Parenting

Thanks everyone! Lots for me to think about...

I have just started prenatal yoga and it seems that it will be pretty useful - although it's way more physical hard work than I expected (I'd better get used to it now, I guess).

Also, I hope I get an inflatable baby from whichever course I end up going with.

Postpartum girdle?

Fri Oct 23 2:47 PM by rowan in Pregnancy & Parenting

Interesting to hear everyone's stories about recovery. I still have issues with some of my ab muscles, I wonder if it would have helped.

OMG, twins! Advice & thoughts?

Mon Oct 19 5:27 AM by BabyTime in Pregnancy & Parenting

Hi :)

I have heard and I have noticed that in twins, one will be very active and one will be dull. Why it is happened with twins? Can anyone give justified answer to my question?

Red Raspberry Leaf capsules - ever helpful for labour or hokum?

Mon Sep 28 3:19 PM by artemiscuous in Pregnancy & Parenting

Oh, this is an interesting discussion and one that I'm finding interesting as I am in the early stages of my second pregnancy.

I really appreciate both perspectives represented here - of modern medicine and of herbalism - and I actually like a middle way of using both, insofar as they are meant to be used (I think both can be and often are misused and misunderstood). I think a well-studied use of herbal remedies can be very complimentary to good medical care. A friend of mine, who is a Western herbalist and clinical researcher, is very evidence-based and really changed my perspective on the place for herbs. It's easy for people to go overboard and claim too many benefits to herbal remedies, to push baseless hokum like homeopathy and chakra balancing, etc., and it's equally easy to denounce it all as unproven, because most clinical studies are not looking at herbs in a double-blind, well-constructed study, particularly in pregnancy, because of the risks if it is somehow dangerous (and many herbs can be, just because they can be quite potent, particularly in a tincture or other concentrated form).

medicated vs. unmedicated birth

Sun Nov 8 9:08 PM by ellarin in Pregnancy & Parenting

I used a midwife and had a home birth so as long as I was staying at home unmedicated was my only option. As I was home I was pretty much able to freely move around and labor however I felt comfortable. I also had access to a birthing pool which was a huge help for pain management and it also helped me to relax and kind of check out. My mantra was "I have to do this, so I will" I mean not exactly the most inspiring mantra out there but it worked for me. I just remember my husband and the midwives telling me repeatedly to breathe in through the nose, out through the mouth which is simple but it did help quite a bit.

I did have to lay on my back through a few of the early contractions for cervical checks and I found it VERY painful. If I had been at a hospital and needed to stay in bed on my back throughout the labor I think I probably would have found the idea of an epidural quite appealing. And ditto to what spacefem said regarding the after part... the most painful memory I have of my labor and delivery was the examination of my tearing after the birth. I think my natural endorphins where all tapped out by the time we got to that portion.

Letting kids use knives (and other dangerous implements)

Mon Nov 2 8:20 PM by lyra211 in Pregnancy & Parenting

When I was 7 we moved down the street from a 6-year-old boy whose dad owned a woodworking company. Little boy and I became pals, and his dad taught the two of us how to whittle not long after that -- as 6- and 7-year-olds messing with some pretty sharp Swiss Army-type knives, we retained all our digits and had a great time making whirligigs. His dad also taught us other basic woodworking, like hammering and whatnot, and other than a smashed finger or two we were none the worse for wear and I grew up pretty handy with some basic tools. No life-threatening injuries, and I can't even remember any slicing of fingers, although it seems as though there must have been some. I think kids are way more capable than we give them credit for, as long as they're properly instructed and supervised (obviously taking into account some judgment of the maturity level of the particular kid involved). It's hard to imagine a butter knife being a danger, and I can remember being pretty comfortable using my grandmother's steak knives to slice up a baked potato from an even younger age than the whittling.

Glucose Tolerance Test Problems

Tue Oct 20 3:26 AM by Bork in Pregnancy & Parenting

Definitely possible! I mean, the idea behind the tests is the same: measure an individual's reaction to a measured amount of glucose. The biology between GDM and T1DM are different, but at the end of the day I would think that the OGTT (glucose test) results would be similar enough. Although I guess there are so many more hormones in play with pregnancy that the results might end up being pretty different. I find it so disconcerting that doctors are like, "well, this test is somewhat unreliable but you should do xyz because FETUS" in cases like this.

We only tested our kids pre and post drink, since it was hard enough to get them to agree to two blood draws!

Altering my mind about pregnancy

Thu Oct 8 10:58 PM by lovernotafighter in Pregnancy & Parenting

Thank you everyone for invaluable opinions. I'm hoping I will not have to wait till my 40's, but I am 34 now, and the earliest I might have kids is probably 37. It will probably also take longer since I am in a same sex marraige, and ttc and all... Another consideration is that my wife is 13 years younger than I and she will be donating her young and healthy egg (hopefully) to me. So, my genetics will not be the only consideration. All factors I think about, and more... :) Thanks again everyone!

that time I got food poisoning when I was pregnant

Sat Sep 19 12:34 PM by spacefem in Pregnancy & Parenting

We have topics and questions all the time about what to eat when you're pregnant, so I wanted to share this charming story of an experience I had while pregnant with my second daughter.

I was only 10 or 11 weeks along and had been dealing with a "managable" level of morning sickness. This means that I could throw up at any time without warning, but in a cute pregnant way, not a dibilitating one. Most times, as long as there was food on my stomach I'd be okay, so I was careful to keep healthy snacks around - my favorite being cheetos, because you know, cheese is dairy right?

I was following all the good internet advice of not eating raw or uncooked foods, no deli meat, no salad bars, no soft cheeses, only low mercury fish, no food out of trunks of cars, etc.

We went to a wedding at a nice hotel. There was a buffet. I was one of the first people in line at the buffet because I had a two year old who looked like she might be hungry so I played that card, you know how it is. The food was delicious - salad with fresh lettuce, rice, beef strogonoff, mixed veggies. Everything that was supposed to be cold was cold and everything that was supposed to be hot was steaming hot.

Vent, advice: How to not be crazy at work...or in general

Wed Nov 4 3:23 PM by Maro in Pregnancy & Parenting

So, my pregnancy hormones are causing me major mood swings right now. I don't necessarily feel ashamed of it, but I'm frustrated enormously by it because I've got a ton of projects at work and a two-year-old to deal with, and I honestly do not have time to sit and cry for 30 minutes every few hours. I really hate being pregnant, for that and other reasons, but right now it's mostly that.

This morning I felt awesome and totally zen and amazing and only vaguely nauseated, and then a couple of things hit at work that I routinely eat for goddamn BREAKFAST and I'm a puddle of tears in my office. Luckily, I work from home so no one can see me, and all I can really do is push through it and keep getting stuff done. But it majorly sucked. Maybe there's no way around it...but if anyone has any ideas for coping with this stuff I'd be grateful. When you Google pregnancy hormones and mood swings the majority of advice is aimed at husbands "surviving" it, which immediately sends me into a rage spiral.

hospital vs homebirth

Sat Oct 24 8:02 PM by careme777 in Pregnancy & Parenting

The numbers don't lie. Home birth is several times riskier. For myself, being a risk averse type, I wouldn't choose it (even if I lived in a place where midwifery was licensed and part of the health care system.)

I'd be curious to know which numbers you're referring to. I chose to do a home birth (living in Canada, with government funded midwifery care) after a LOT of research (on an unrelated note, we ended up transferring to the hospital for a C-section during the pushing phase because baby wasn't turned correctly).

I read most of skepticalOB while trying to make my decision and did a basic (given my limited access to databases) lit review. My conclusion was that skepticalOB might have a point when discussing home birth in the US, because of the way midwifery care is stratified into certified nurse midwives and lay midwives. In mostly every other developed country with midwifery care, however, there is no conclusive evidence one way or the other that home birth is less safe than hospital birth for women with low risk pregnancies.


Mon Oct 19 1:05 PM by Sonic# in Pregnancy & Parenting

^ Should I stop doing one pro-health activity proven to stymie the spread of disease just because I have another one? It seems inaccurate to use cholera, a disease for which children in Western countries are not usually vaccinated for precisely the reasons you describe, to talk about all vaccinations. A better example is whooping cough, a highly contagious bacterial infection which doesn't need waterborne or foodborne vectors in order to travel and which vaccines prevent.

I don't think anyone here was saying vaccines are the only relevant factor. I heard Spacefem saying they're an important factor because even healthy living and good infrastructure won't prevent the spread of disease, and even good country living (not city living) is no panacea.

A bit aside from the topic, but I'm getting a flu vaccine this year because one of my colleagues cannot receive vaccinations due to a condition that suppresses her immune system. If I said, "Modern society is much cleaner nowadays and we eat a lot better, so I'm going to opt out of the vaccine and expect you to tough it out," I'd expect her to yell at me. Now, some of the hallmarks of that decision differ - I'm an adult who voluntarily takes the vaccine. The impact is similar - I reduce for the more vulnerable people around me (kids, elderly, anyone else with suppressed immune systems) the risks associated with infection.

Real stats for C-Sections?

Sun Oct 4 2:18 AM by Gnarlbanya in Pregnancy & Parenting

Thinking about this topic a little more, I think it's important that we remember that statistics just indicate trends and don't actually tell much of a story as far as individual circumstances go. By that I mean that while in some countries the c-section rate is statistically higher than in other places, it doesn't mean that an individual's decision to have a c-section in those countries is necessarily a flawed one. Nor does it mean that all doctors in those countries are scalpel-happy and just want to get babies out so they can take off to play golf or go for lunch, as I've seen it put on other pregnancy forums (not here).

If I do a brief statistical analysis of friends/acquaintances etc who have given birth in the last few years, the majority had vaginal births, everything from quick and uncomplicated to lengthy and forceps delivery. I can't think of any who had c-sections as a personal choice rather than for a medical reason. Those who had c-sections either had scheduled ones for good reason (obstruction due to fibroids, placenta previa, breech after unsuccessful ECV) or an emergency one for good reason (pre-eclampsia, fetal distress, placental abruption etc). Australia apparently has a c-section rate of 20-25% which this sample would accord with. But given the reasons for the c-sections, I do wonder when I read that the WHO recommends a c-section rate of 10-15%, who exactly should have been turned away from this limited sample?

Prenatal genetic testing

Thu Sep 17 9:08 AM by rowan in Pregnancy & Parenting

MOD HAT: I have moved the vaccination discussion to a new thread. Please discuss vaccines there.