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 August 25th, 2016.

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
Thursday July 21st, 2016 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Friday July 22nd, 2016 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Saturday July 23rd, 2016 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Sunday July 24th, 2016 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Monday July 25th, 2016 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Tuesday July 26th, 2016 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Wednesday July 27th, 2016 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Thursday July 28th, 2016 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Friday July 29th, 2016 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Saturday July 30th, 2016 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Sunday July 31st, 2016 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Monday August 1st, 2016 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Tuesday August 2nd, 2016 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Wednesday August 3rd, 2016 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Thursday August 4th, 2016 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Friday August 5th, 2016 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Saturday August 6th, 2016 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Sunday August 7th, 2016 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Monday August 8th, 2016 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Tuesday August 9th, 2016 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Wednesday August 10th, 2016 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Thursday August 11th, 2016 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Friday August 12th, 2016 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Saturday August 13th, 2016 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Sunday August 14th, 2016 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Monday August 15th, 2016 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Tuesday August 16th, 2016 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Wednesday August 17th, 2016 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Thursday August 18th, 2016 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Friday August 19th, 2016 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Saturday August 20th, 2016 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Sunday August 21st, 2016 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Monday August 22nd, 2016 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Tuesday August 23rd, 2016 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Wednesday August 24th, 2016 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Thursday August 25th, 2016 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Friday August 26th, 2016 40W, 1D 3.97% 53.98% 7.9% 8% 8.6% 25.1% 40.4% 54%
Saturday August 27th, 2016 40W, 2D 3.91% 57.93% 7.8% 15.9% 9.3% 26.7% 42.5% 56.2%
Sunday August 28th, 2016 40W, 3D 3.81% 61.79% 7.6% 23.6% 10% 28.2% 44.5% 58.5%
Monday August 29th, 2016 40W, 4D 3.68% 65.54% 7.4% 31.1% 10.7% 29.8% 46.6% 60.6%
Tuesday August 30th, 2016 40W, 5D 3.52% 69.15% 7% 38.3% 11.4% 31.3% 48.6% 62.7%
Wednesday August 31st, 2016 40W, 6D 3.33% 72.57% 6.7% 45.1% 12.1% 32.9% 50.5% 64.7%
Thursday September 1st, 2016 41W, 0D 3.12% 75.8% 6.2% 51.6% 12.9% 34.4% 52.4% 66.6%
Friday September 2nd, 2016 41W, 1D 2.9% 78.81% 5.8% 57.6% 13.7% 36% 54.3% 68.5%
Saturday September 3rd, 2016 41W, 2D 2.66% 81.59% 5.3% 63.2% 14.4% 37.5% 56.1% 70.2%
Sunday September 4th, 2016 41W, 3D 2.42% 84.13% 4.8% 68.3% 15.2% 39% 57.9% 71.9%
Monday September 5th, 2016 41W, 4D 2.18% 86.43% 4.4% 72.9% 16.1% 40.5% 59.6% 73.5%
Tuesday September 6th, 2016 41W, 5D 1.94% 88.49% 3.9% 77% 16.9% 42% 61.3% 75.1%
Wednesday September 7th, 2016 41W, 6D 1.71% 90.32% 3.4% 80.6% 17.7% 43.4% 62.9% 76.4%
Thursday September 8th, 2016 42W, 0D 1.5% 91.92% 3% 83.8% 18.6% 44.8% 64.5% 77.8%
Friday September 9th, 2016 42W, 1D 1.3% 93.32% 2.6% 86.6% 19.5% 46.3% 65.9% 79.2%
Saturday September 10th, 2016 42W, 2D 1.11% 94.52% 2.2% 89% 20.3% 47.6% 67.3% 80.5%
Sunday September 11th, 2016 42W, 3D 0.94% 95.54% 1.9% 91.1% 21.1% 48.9% 68.8% 81.6%
Monday September 12th, 2016 42W, 4D 0.79% 96.41% 1.6% 92.8% 22% 50.1% 70.2% 82.7%
Tuesday September 13th, 2016 42W, 5D 0.66% 97.13% 1.3% 94.3% 23% 51.6% 71.4% 83.6%
Wednesday September 14th, 2016 42W, 6D 0.54% 97.72% 1.1% 95.4% 23.7% 53.1% 72.8% 84.6%
Thursday September 15th, 2016 43W, 0D 0.44% 98.21% 0.9% 96.4% 24.6% 54.2% 73.7% 85.5%
Friday September 16th, 2016 43W, 1D 0.35% 98.61% 0.7% 97.2% 25.2% 55.4% 74.8% 86.3%
Saturday September 17th, 2016 43W, 2D 0.28% 98.93% 0.6% 97.9% 26.2% 56.1% 75.7% 87.9%
Sunday September 18th, 2016 43W, 3D 0.22% 99.18% 0.4% 98.4% 26.8% 57.3% 76.8% -%
Monday September 19th, 2016 43W, 4D 0.18% 99.38% 0.4% 98.8% 29% 58.1% 79% -%
Tuesday September 20th, 2016 43W, 5D 0.14% 99.53% 0.3% 99.1% 29.8% 59.6% -% -%
Wednesday September 21st, 2016 43W, 6D 0.1% 99.65% 0.2% 99.3% 28.6% 62.9% -% -%
Thursday September 22nd, 2016 44W, 0D 0.08% 99.74% 0.2% 99.5% 30.8% -% -% -%
Friday September 23rd, 2016 44W, 1D 0.06% 99.81% 0.1% 99.6% 31.6% -% -% -%
Saturday September 24th, 2016 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 (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.

Cry it out vs. Attachment

Thu Aug 18 9:39 PM by melsbells in Pregnancy & Parenting

Everything I remember reading about this seemed fairly contradictory. As far as I could tell, there aren't actually any good studies available, which I suppose is expected when the subject matter is infant behavior. We ended up leaning toward attachment parenting because it fit our personalities better and then the kid's personality seemed to pull us decidedly in that direction. I was even convinced by doctors and nurses in the hospital to bed share, even though I was opposed to it from what I now see as fear mongering in the U.S. about safety.


it gets better thread for parents

Fri Jul 29 1:26 AM by curlybae in Pregnancy & Parenting

It's true though. You don't get a good night's sleep until they're an adult. Looking back, I don't think my mom slept a wink my baby brother was born lol


Public Service Announcement: Furniture Anchors!

Fri Jul 1 5:17 AM by cwbyrvr in Pregnancy & Parenting

I do find it very interesting to find that IKEA is recalling furniture because people don't secure it to walls... I was given anchors with all of the stuff I've bought from there. Though maybe that's only a somewhat recent thing? It was over a half a year ago that I bought stuff from there, though.

And I didn't use the anchors... I guess I am about to be an aunt and it might be a good idea to get that stuff secured in case I ever end up watching my niece here. Hadn't really worried about it prior because there was literally never going to be a time I'd have kids running around this place. The likelihood of my niece ever being here is pretty damn low too, but I wouldn't say 0%.


Pregnancy Guidebooks for Cool Moms (humor)

Wed May 11 3:39 PM by rowan in Pregnancy & Parenting

One of my friends is part of this magazine. She didn't write this one but it's pretty hilarious.

http://theoffingmag.com/wits-end/pregna ... cool-moms/

Anyone want to come up with our own "Guidebook" titles?

spoiler:
the one about inducing labor by setting your hair on fire is my favorite


stuttering at the end of words

Thu Apr 28 9:21 PM by Sonic# in Pregnancy & Parenting

I don't think it's a cause for immediate concern, but my experience would lead me to talk to a doctor about it. I didn't have a stutter when I was 2. I had language delay. I didn't learn language when kids typically do. Needless to say, I was a very frustrated little kid. When my parents and my pediatrician caught on to it, I had to spend a few years seeing a speech pathologist.

I've read that stuttering is at least partly psychological, but I really can't say more than that. If nothing else, I'd just want to know that his frustration is a necessary part of development like teething and not something that can be avoided.


Do you use boil bags?

Mon Aug 8 3:20 PM by Sonic# in Pregnancy & Parenting

All I can think of is the Arrested Development episode where George Bluth Sr. has a hot tub installed in his attic hiding place so that he can boil food in the bag.

I've not boiledfood in a bag, but not due to any aversion.


How NOT to help parents with a newborn

Fri Jul 22 6:11 PM by missmay in Pregnancy & Parenting

oh, lord, i am so tired of people telling me to "enjoy it!" regarding my newborn. and asking me if she is a "good baby." how could a baby be bad? and how does it make me enjoy her more to be reminded to do so? i imagine that if i was depressed and had a colicky baby these questions would be even more obnoxious.


Kids are full of LIES

Sun May 22 2:29 PM by rowan in Pregnancy & Parenting

Don't be silly monk, everyone knows a good conglomerate goes better with milk


young kids, consent and bodily autonomy

Mon May 2 8:46 PM by monk in Pregnancy & Parenting

I think it depends on the child. Do you ask a newborn if it needs it's diaper changed? Obviously no. Do you help a 13 year old get dressed? Obviously no. Somewhere in there the child matures to the point where they should learn that they own their bodies even if they don't have all the privileges an adult does. This age is going to vary wildly between different children (by widly, I would say 3 year range). I would guess that some kids might be ready for this lesson as early as 3 while others not until they're about to go school. Actually that's a pretty good benchmark, because if you're going to put them in a group with other kids they don't know they should know the rules about touching or being touched.

As far as kissing Grandma, maybe they shouldn't have to do it, but making them do this social communcation helps get them ready for all the other social communication that will be forced on them later. Plus, grandma needs that love to help HER be healthy.


test out my new name picker

Fri Apr 15 11:41 PM by rowan in Pregnancy & Parenting

my neighbor's dog is named Gunner? Makes more sense for a bird dog....


How to Announce Baby #4?

Mon Aug 1 10:44 PM by rowan in Pregnancy & Parenting

eh go ahead and eat them. I recommend ketchup, though. Or hot sauce.

Oh and congratulations and all that, it'll be fine. :) People do get weird but here are some random responses:
"well, I guess we were wrong!" cheerfully
"Shit, we we were wrong. OH well.
"IDK do you think we should get rid of one of the others?"
"You want one?"
"Well we weren't sure the first three would be enough sustenance when the apocalypse comes"
"We have W girls and Z boys, we're hoping for something in between"
"Actually we're hoping it's a cat"
"Did you realize that we just sent a new spacecraft to Jupiter? Isn't that exciting!"


Denial Trends?

Thu Jul 21 7:24 PM by SameMom in Pregnancy & Parenting

Sorry, if I was not able to mention other details. Actually, I have a (US) medicare insurance. And I am particularly referring to this denial management software which help clients with their claims. Thanks for your reply. :)


minimalist kids birthday parties

Sun May 15 9:19 PM by melsbells in Pregnancy & Parenting

For the first two birthdays, we tried to make some special food and splurge on interesting fruit. If I lived closer to friends, I would want to throw a get-together as an excuse to see my friends, celebrate our survival of another year. I don't think my kid would actually be into that though. They are turning out to be quite introverted and shy.


7th Birthday - Theme Suggestion

Mon May 2 8:18 PM by melsbells in Pregnancy & Parenting

I met a kid about that age who had a geo-caching birthday party and another one who had a roller-skating party. Both sounded awesome. The first one sounded like a whole lot of work to put together.


Criminalization of drug use during pregnancy to end in Tennessee

Tue Mar 29 2:48 AM by Amuro in Pregnancy & Parenting

Actually I think it would be better if the penalty was rehab and being sent to a therapist. It's pretty dumb to criminalize it especially because there is an almost certainty custody will be taken away. Why not try and fix the problem with addiction so there is less of a strain on social services. There should be increased awareness but what idiot doesn't know drugs are bad for you and worse if your pregnant. If you are addicted to drugs you obviously are thinking about getting high and that's about it.