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, 2014.

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
Saturday November 15th, 2014 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Sunday November 16th, 2014 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Monday November 17th, 2014 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Tuesday November 18th, 2014 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Wednesday November 19th, 2014 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Thursday November 20th, 2014 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Friday November 21st, 2014 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Saturday November 22nd, 2014 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Sunday November 23rd, 2014 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Monday November 24th, 2014 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Tuesday November 25th, 2014 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Wednesday November 26th, 2014 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Thursday November 27th, 2014 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Friday November 28th, 2014 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Saturday November 29th, 2014 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Sunday November 30th, 2014 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Monday December 1st, 2014 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Tuesday December 2nd, 2014 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Wednesday December 3rd, 2014 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Thursday December 4th, 2014 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Friday December 5th, 2014 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Saturday December 6th, 2014 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Sunday December 7th, 2014 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Monday December 8th, 2014 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Tuesday December 9th, 2014 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Wednesday December 10th, 2014 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Thursday December 11th, 2014 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Friday December 12th, 2014 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Saturday December 13th, 2014 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Sunday December 14th, 2014 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Monday December 15th, 2014 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Tuesday December 16th, 2014 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Wednesday December 17th, 2014 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Thursday December 18th, 2014 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Friday December 19th, 2014 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Saturday December 20th, 2014 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Sunday December 21st, 2014 40W, 1D 3.97% 53.98% -% -% 8.6% 25.1% 40.4% 54%
Monday December 22nd, 2014 40W, 2D 3.91% 57.93% -% -% 9.3% 26.7% 42.5% 56.2%
Tuesday December 23rd, 2014 40W, 3D 3.81% 61.79% -% -% 10% 28.2% 44.5% 58.5%
Wednesday December 24th, 2014 40W, 4D 3.68% 65.54% -% -% 10.7% 29.8% 46.6% 60.6%
Thursday December 25th, 2014 40W, 5D 3.52% 69.15% -% -% 11.4% 31.3% 48.6% 62.7%
Friday December 26th, 2014 40W, 6D 3.33% 72.57% -% -% 12.1% 32.9% 50.5% 64.7%
Saturday December 27th, 2014 41W, 0D 3.12% 75.8% -% -% 12.9% 34.4% 52.4% 66.6%
Sunday December 28th, 2014 41W, 1D 2.9% 78.81% -% -% 13.7% 36% 54.3% 68.5%
Monday December 29th, 2014 41W, 2D 2.66% 81.59% -% -% 14.4% 37.5% 56.1% 70.2%
Tuesday December 30th, 2014 41W, 3D 2.42% 84.13% -% -% 15.2% 39% 57.9% 71.9%
Wednesday December 31st, 2014 41W, 4D 2.18% 86.43% -% -% 16.1% 40.5% 59.6% 73.5%
Thursday January 1st, 2015 41W, 5D 1.94% 88.49% -% -% 16.9% 42% 61.3% 75.1%
Friday January 2nd, 2015 41W, 6D 1.71% 90.32% -% -% 17.7% 43.4% 62.9% 76.4%
Saturday January 3rd, 2015 42W, 0D 1.5% 91.92% -% -% 18.6% 44.8% 64.5% 77.8%
Sunday January 4th, 2015 42W, 1D 1.3% 93.32% -% -% 19.5% 46.3% 65.9% 79.2%
Monday January 5th, 2015 42W, 2D 1.11% 94.52% -% -% 20.3% 47.6% 67.3% 80.5%
Tuesday January 6th, 2015 42W, 3D 0.94% 95.54% -% -% 21.1% 48.9% 68.8% 81.6%
Wednesday January 7th, 2015 42W, 4D 0.79% 96.41% -% -% 22% 50.1% 70.2% 82.7%
Thursday January 8th, 2015 42W, 5D 0.66% 97.13% -% -% 23% 51.6% 71.4% 83.6%
Friday January 9th, 2015 42W, 6D 0.54% 97.72% -% -% 23.7% 53.1% 72.8% 84.6%
Saturday January 10th, 2015 43W, 0D 0.44% 98.21% -% -% 24.6% 54.2% 73.7% 85.5%
Sunday January 11th, 2015 43W, 1D 0.35% 98.61% -% -% 25.2% 55.4% 74.8% 86.3%
Monday January 12th, 2015 43W, 2D 0.28% 98.93% -% -% 26.2% 56.1% 75.7% 87.9%
Tuesday January 13th, 2015 43W, 3D 0.22% 99.18% -% -% 26.8% 57.3% 76.8% -%
Wednesday January 14th, 2015 43W, 4D 0.18% 99.38% -% -% 29% 58.1% 79% -%
Thursday January 15th, 2015 43W, 5D 0.14% 99.53% -% -% 29.8% 59.6% -% -%
Friday January 16th, 2015 43W, 6D 0.1% 99.65% -% -% 28.6% 62.9% -% -%
Saturday January 17th, 2015 44W, 0D 0.08% 99.74% -% -% 30.8% -% -% -%
Sunday January 18th, 2015 44W, 1D 0.06% 99.81% -% -% 31.6% -% -% -%
Monday January 19th, 2015 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.

non-religious parents raise okay kids after all

Wed Sep 2 3:37 AM by AndrewZealand in Pregnancy & Parenting

However, one thing I remember clearly from my childhood is being very afraid of death.

I remember when I first realized that we die when we get old. I told my best friend at the time and he got really upset. I never quite had the need for an afterlife, though I remember at about 10 I conceived that when we died maybe we came back again as someone else. This was before I knew that someone else had already thought of that :P

Presently I'm still open to the idea of some sort of afterlife when we die. One thing I find inspirational when I'm depressed is the thought that there might be some sort of new and interesting afterlife when we die. It can give me energy to keep on with this life. But the idea of eternal punishment for our sins in the afterlife? I'd say to the average man that's the same as "Life's a bitch and then you die and then you go to hell and suffer". The idea that we MIGHT get punished for our sins when we die, for most of us, only serves to make our lives more fearful and miserable and then of course when we die we may well find that no such punishment exists. Like the saying goes "Cheer up, it might never happen". The only usefulness I think of for the idea of afterlife retribution, is something with which to scare a tyrant who is so powerful that apparently nothing in this life can stop him or her abusing people and nature. By telling them that there might be something in the afterlife holding them to account, you might actually scare them into reconsidering their behaviour. But I'd say that for most people, hell or other afterlife punishment, is an unnecessary fear.


Happy Birthday, Baby Bird!

Thu Aug 27 12:57 PM by ablotial in Pregnancy & Parenting

Cute kids, and I love the cupcake theme!


mom guilt bingo

Sun Aug 23 11:06 AM by ohbonobogirl in Pregnancy & Parenting

Adding to the newborn edition:
Knowingly fell asleep on the couch with baby on your chest because...sleep...
Used a tablet or phone to surf net or play games while nursing rather than cherishing every moment
Took baby out in public solely because it's really great to hear strangers compliment your adorable little being.


teething necklaces

Tue Aug 4 7:12 PM by DarkOne in Pregnancy & Parenting

They'll chew on anything and everything. And I think you may have the scale wrong. These are large silicone beads. Think of it as a teething/chewing toy that is long enough to be worn around mom's neck. This isn't a string of pearls that will break if you tug on it and you'll and up with a mess of pearls on the floor or in baby's mouth. Google images for "babies and chew beads".
http://homemademothering.com/wp-content/uploads/2013/04/DSC7453.jpg
http://www.frugalcouponliving.com/wp-content/uploads/2012/05/chew-beads.jpg
And these are not at all related to those dumb amber necklaces...


do you have a parenting goal?

Sun Jul 26 5:16 PM by rosefox in Pregnancy & Parenting

I'm definitely in the "happy healthy child is my only goal" camp. I know some people who are superstars in their chosen fields. From what I can tell, being a superstar is completely exhausting and often really psychologically taxing. So if my kid isn't naturally inclined that way, I certainly don't intend to push them.

If I'm hoping for anything, I hope they'll end up being a quirky artsy/techy type like just about everyone else in the family. But my brother's a corporate lawyer and I love him anyway, so even if our kid turns out to be a white sheep, they'll just bond with Uncle A and it'll all be fine. :)


Braxton Hicks questions

Fri Aug 28 5:10 PM by geerlady in Pregnancy & Parenting

Was just in the hospital for a pre-term labour false alarm earlier this week.

My Braxton Hicks have changed this time around to be sometimes painful, period-like cramps extending to my lower back with contractions that are fairly regular (every 10 to 15 minutes regardless of what I am doing). But they have been medically confirmed to still just be Braxton Hicks :o

As a general comment, my BH have always been symmetric, so symmetry was never a good marker for me.

So... second time around and I still can't tell the difference :)


What new thing did your baby do this week?

Mon Aug 24 5:56 PM by Nachos in Pregnancy & Parenting

It's not my baby, but my sister taught my best friend's baby how to fist bump and I taught her how to say yolo. Heh.


What the Hell just entered my earhole?

Mon Aug 17 11:34 AM by DarkOne in Pregnancy & Parenting

Oh that reminded me of a friend's kid... My friend, her 6-yr old son and her 9-yr old daughter were driving to school in the morning, when the son proudly declared "When I grow up I want to be a racist." My friend said she went O_O and her daughter went on a rant as to how horrible of an idea that was... The son was all sad and confused when he responded "But I really love race cars!"

That cracked me up.


Kids books we hate

Mon Aug 3 1:10 PM by Sonic# in Pregnancy & Parenting

I absolutely loved at least one of the Berenstain Bears books (one based off of the Tortoise and the Hare), but I also hate at least one of them. The Berenstain Bears and the Trouble With Chores features a Mama Bear exasperated that no one is doing chores, with the kid bears and Papa Bear keep excusing themselves out of doing them. Rather than coming to some equitable distribution of labor by the end, the house gets really bad and the kids and pop finally binge clean. The situation didn't seem solved; Mama Bear just seemed pacified.


for all you moms and future moms

Tue Jul 21 2:28 AM by DarkOne in Pregnancy & Parenting

Eek and here I was about to say this felt like a tame version of Mother Lover.


Body Betrayal

Thu Aug 27 8:44 PM by mathnome in Pregnancy & Parenting

Ugh.

I'm currently 37 weeks, and while almost all my immediate coworkers have been super supportive of my being at work (and planning to continue being at work), I got a "tsk tsk" from another woman the other day about not taking my leave yet, and she hasn't been the first one. (Interestingly, so far it's only been the women who seem to think I'm supposed to leave already.)

Anyway, my line has been, "I'm really enjoying my project right now. I might as well enjoy it while I can!" (Which is true, and also generally shuts them up.)

Good luck! I hope the BP stays under the magic threshold.


What did you hate hearing when you were pregnant?

Mon Aug 24 11:52 AM by DarkOne in Pregnancy & Parenting


3. I think you're putting on too much weight. You know it''s going to make it harder to get your body back. (I'm 6 months post baby today, so now the comments have turned to "I told you!")


WHAAAAAT????
http://static1.wikia.nocookie.net/__cb20130207210531/disney/images/thumb/0/0b/Hercules-disneyscreencaps.com-1020.jpg/640px-Hercules-disneyscreencaps.com-1020.jpg


let's list our favorite children's books

Tue Aug 11 3:49 AM by DarkOne in Pregnancy & Parenting

As a grade school kid, I spent a lot of time perusing dictionaries, atlases and world almanacs. I blame it on my Big Bird's Sesame Street Dictionary, which was awesome:

https://img1.etsystatic.com/000/0/6267461/il_570xN.298036045.jpg
http://www.joemathieu.com/images/sesame_street_dictionary_open_book.jpg

Did anyone else own these? I have the full set stashed somewhere for when my kid is old enough.


RIE parenting

Sat Aug 1 2:09 AM by ohbonobogirl in Pregnancy & Parenting

I encountered this randomly the other day. Now I need to go dig some more into it...


the wonder weeks: practical help for parents or self-fulfilling quackery?

Mon Jul 20 2:29 AM by geerlady in Pregnancy & Parenting

I am actually a big fan of the wonder weeks. I found it better than most popular level books looking at infant development. My son was right on the clock for the fussy/happy times, and it was interesting to look for the new skills that I might not have noticed if I hadn't been watching for them.

On the other hand, I stumbled upon this accidentally, so didn't have any hype surrounding it. I also read the author biographies before picking up the book, so took everything with a grain of salt knowing that 1) the authors specialized in chimpanzees, not humans, and developed their theories based on chimps; 2) the bulk of the research is greater than 20 years old and so much of the book is out-dated; and 3) given #'s 1&2, incidental parenting advice had to be filtered.

That said, I still found the book useful and regularly recommend it to people.