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, 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
Friday August 21st, 2015 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Saturday August 22nd, 2015 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Sunday August 23rd, 2015 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Monday August 24th, 2015 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Tuesday August 25th, 2015 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Wednesday August 26th, 2015 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Thursday August 27th, 2015 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Friday August 28th, 2015 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Saturday August 29th, 2015 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Sunday August 30th, 2015 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Monday August 31st, 2015 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Tuesday September 1st, 2015 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Wednesday September 2nd, 2015 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Thursday September 3rd, 2015 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Friday September 4th, 2015 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Saturday September 5th, 2015 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Sunday September 6th, 2015 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Monday September 7th, 2015 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Tuesday September 8th, 2015 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Wednesday September 9th, 2015 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Thursday September 10th, 2015 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Friday September 11th, 2015 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Saturday September 12th, 2015 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Sunday September 13th, 2015 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Monday September 14th, 2015 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Tuesday September 15th, 2015 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Wednesday September 16th, 2015 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Thursday September 17th, 2015 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Friday September 18th, 2015 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Saturday September 19th, 2015 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Sunday September 20th, 2015 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Monday September 21st, 2015 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Tuesday September 22nd, 2015 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Wednesday September 23rd, 2015 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Thursday September 24th, 2015 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Friday September 25th, 2015 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Saturday September 26th, 2015 40W, 1D 3.97% 53.98% -% -% 8.6% 25.1% 40.4% 54%
Sunday September 27th, 2015 40W, 2D 3.91% 57.93% -% -% 9.3% 26.7% 42.5% 56.2%
Monday September 28th, 2015 40W, 3D 3.81% 61.79% -% -% 10% 28.2% 44.5% 58.5%
Tuesday September 29th, 2015 40W, 4D 3.68% 65.54% -% -% 10.7% 29.8% 46.6% 60.6%
Wednesday September 30th, 2015 40W, 5D 3.52% 69.15% -% -% 11.4% 31.3% 48.6% 62.7%
Thursday October 1st, 2015 40W, 6D 3.33% 72.57% -% -% 12.1% 32.9% 50.5% 64.7%
Friday October 2nd, 2015 41W, 0D 3.12% 75.8% -% -% 12.9% 34.4% 52.4% 66.6%
Saturday October 3rd, 2015 41W, 1D 2.9% 78.81% -% -% 13.7% 36% 54.3% 68.5%
Sunday October 4th, 2015 41W, 2D 2.66% 81.59% 14.4% 0% 14.4% 37.5% 56.1% 70.2%
Monday October 5th, 2015 41W, 3D 2.42% 84.13% 13.1% 13.8% 15.2% 39% 57.9% 71.9%
Tuesday October 6th, 2015 41W, 4D 2.18% 86.43% 11.8% 26.3% 16.1% 40.5% 59.6% 73.5%
Wednesday October 7th, 2015 41W, 5D 1.94% 88.49% 10.5% 37.5% 16.9% 42% 61.3% 75.1%
Thursday October 8th, 2015 41W, 6D 1.71% 90.32% 9.3% 47.4% 17.7% 43.4% 62.9% 76.4%
Friday October 9th, 2015 42W, 0D 1.5% 91.92% 8.1% 56.1% 18.6% 44.8% 64.5% 77.8%
Saturday October 10th, 2015 42W, 1D 1.3% 93.32% 7.1% 63.7% 19.5% 46.3% 65.9% 79.2%
Sunday October 11th, 2015 42W, 2D 1.11% 94.52% 6% 70.2% 20.3% 47.6% 67.3% 80.5%
Monday October 12th, 2015 42W, 3D 0.94% 95.54% 5.1% 75.8% 21.1% 48.9% 68.8% 81.6%
Tuesday October 13th, 2015 42W, 4D 0.79% 96.41% 4.3% 80.5% 22% 50.1% 70.2% 82.7%
Wednesday October 14th, 2015 42W, 5D 0.66% 97.13% 3.6% 84.4% 23% 51.6% 71.4% 83.6%
Thursday October 15th, 2015 42W, 6D 0.54% 97.72% 2.9% 87.6% 23.7% 53.1% 72.8% 84.6%
Friday October 16th, 2015 43W, 0D 0.44% 98.21% 2.4% 90.3% 24.6% 54.2% 73.7% 85.5%
Saturday October 17th, 2015 43W, 1D 0.35% 98.61% 1.9% 92.4% 25.2% 55.4% 74.8% 86.3%
Sunday October 18th, 2015 43W, 2D 0.28% 98.93% 1.5% 94.2% 26.2% 56.1% 75.7% 87.9%
Monday October 19th, 2015 43W, 3D 0.22% 99.18% 1.2% 95.5% 26.8% 57.3% 76.8% -%
Tuesday October 20th, 2015 43W, 4D 0.18% 99.38% 1% 96.6% 29% 58.1% 79% -%
Wednesday October 21st, 2015 43W, 5D 0.14% 99.53% 0.8% 97.4% 29.8% 59.6% -% -%
Thursday October 22nd, 2015 43W, 6D 0.1% 99.65% 0.5% 98.1% 28.6% 62.9% -% -%
Friday October 23rd, 2015 44W, 0D 0.08% 99.74% 0.4% 98.6% 30.8% -% -% -%
Saturday October 24th, 2015 44W, 1D 0.06% 99.81% 0.3% 99% 31.6% -% -% -%
Sunday October 25th, 2015 44W, 2D 0.04% 99.87% 0.2% 99.3% 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. Waldenstrรถ) 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.

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?

hospital vs homebirth

Sat Oct 3 12:20 AM by Aum in Pregnancy & Parenting

^ I think in the greater diaspora of documentaries on birthing styles, Business of Being Born is pretty good. But I understand your frustration, being in the U.S. The free market there kind of lets people do what they want in a lot of ways. The system in Canada is different. Midwifery is a university program, a bachelor's degree, usually as an attachment to nursing schools. They get trained in modern medicine and can integrate their lineage birthing traditions with modern cutting edge understandings. It doesn't have to be either/or. Kind of disturbing to hear that people in the U.S. can claim to be midwives with a high school diploma. That sounds like a recipe for disaster. I would hope that most people are interrogating the qualifications of their midwife before they commit.

My sister had her first kid at home, the second at a hospital. Both were appropriate, in different contexts. She said that the hospital offered her different methods and she refused them all. Her baby was breech so she had to be in the hospital, but in the end the baby turned and everything happened naturally.

Letting kids use knives (and other dangerous implements)

Mon Sep 28 8:51 PM by ablotial in Pregnancy & Parenting

We didn't have knives at home until I was ... 9 or 10? But they gave us butter knives with school lunch right from the get go, so ... yeah. I never complained about this at home though because I was lazy and liked to be pampered and have my mom cut up my food and spread the butter for me :P

And I did have trouble when they finally gave me real (actually sharp) knives. Steak knives were fine because they were serrated, but I had trouble with paring knives telling which side was the sharp side and often used them upside down trying to saw through something with the dull edge. I finally learned to look closely and learn the difference when my dad got frustrated with how slow it was going for me and slammed his hand down on the knife to push it through (a carrot? celery? can't remember now) and almost cut off his thumb :/

What do you wish you had known?

Fri Sep 18 3:14 PM by rowan in Pregnancy & Parenting

Hm. I dunno, I don't really feel quite as terrified about things as I did for the first several years. Which isn't to say there aren't moments...

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.


Sun Oct 4 12:48 AM by Aum in Pregnancy & Parenting

Aum, you claimed earlier that your medical practice was incapable of doing harm, but please be aware that your medical advice to first put off vaccinating and ignore vaccination schedules and then to be lax about enforcing herd immunity/limiting contact with potential disease vectors actually has the potential to cause a great deal of harm.

My practice has never harmed anybody.

This is just a discussion, I'm not giving advice. I didn't even share my medical title or real name here. Nice attempt at trying to shame me. It won't work though.

It is not as rare as you'd think. Also, although you become MORE contagious once you become symptomatic with pertussis, you can still be very contagious before your symptoms appear. My turn for a personal story:
I caught pertussis as an adult. I had my vaccinations, which gave me the benefit of having a much milder case that I otherwise would have and removed my risk from all the serious complications that can arise from the disease. It still really sucked though, and it was more than three months before I returned to any semblance of normal health. I caught it while working with a group of adults from a religion that does not believe in vaccination. None of them were symptomatic until 36-48 hours after I had worked with them. They spread it to quite a few people during this time. It was determined to be pertussis rather quickly once their symptoms appeared, because most of the unvaccinated individuals ended up in the hospital with severe complications. They also spread it to a few babies, all of which ended up with extended stays in the hospital. Ever seen a baby with whooping cough? I'll spare you the graphic details, but be assured that it is extremely frightening for everyone involved. One of the babies ended up with chronic emphysema as a result of the disease; the others recovered fully after their hospital stay. Either way, such precautions aren't paranoia; they are simple steps people can take to help prevent disease. This is especially important for parents taking your advice on delaying vaccinations.

medicated vs. unmedicated birth

Fri Oct 2 10:46 PM by spacefem in Pregnancy & Parenting

This came up a little bit in some topics but I figured I'd make an on-purpose topic on it, because I have some experience, on both sides interestingly enough.

I've now had two babies, one without any medication in labor and one with an epidural. And I can honestly say that if were to go for a third (not in the plans, but hey) I... have no idea what I'd do. So that's my answer for the perfect birth plan: whatever.

Here are some things I do know:

Those natural birth techniques really do help with managing painful contractions. With my first it was lamaze breathing and counting that helped me ride out each one. With my second the pain was different, constant back labor and the contractions felt a lot worse, so the bradley method of "stick to this position, don't move, and relax every muscle in your body" helped the most. So even between natural birth methods there's no perfect one. But it helps to be familiar with some, take a class, read a book, practice.

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).

public service announcement: eating lunch with your friend who's a new mom

Fri Sep 18 10:27 AM by Nachos in Pregnancy & Parenting

I honestly love holding other people's babies while they're eating. Did this for a new mum friend who needed to go to the loo and she turned back a few times because the baby was crying, but as soon as she was out of sight, baby was just fine.

let's discuss childhood injuries

Thu Sep 10 3:19 AM by DarkOne in Pregnancy & Parenting

When I was about 7 or 8 I was riding my bike and rode off the curb, flew off the seat, landed on the tube, and somehow managed to get a cut in my vaginal area. Apparently, it bled like a mofo. It turned out to be only a small cut, but I can only imagine what my mom felt like when her 8yo showed up at her door crying hysterically and bleeding profusely from her crotch.

OMG, twins! Advice & thoughts?

Sat Oct 3 8:19 AM by BethReed in Pregnancy & Parenting

Hi there,
I'm new here... and just starting my second trimester of pregnancy with twins. They are fraternal, conceived via IVF, and it's my first healthy pregnancy. We have had some painful fertility misadventures in the past, so I'm just grateful and excited to be this far along, with healthy scans and test results thus far!

As I start to realize that these twinsies are most likely here to stay (!), I'm also starting to feel pretty unprepared, especially in terms of what supplies we'll need. There seem to be a lot of irritating "essential baby supply" articles that are thinly disguised ads for things like $800 strollers, which are anyway designed for singletons, so they're not even relevant to our situation! And of course, I think my feeling of being unprepared on the logistical front is probably masking my feelings of unpreparedness on the emotional / physical / marriage / family front as well.

So... I'd love to hear... what do you think my hubby and I should know about parenting twins? Or parenting at all?

Altering my mind about pregnancy

Mon Sep 28 9:09 PM by ablotial in Pregnancy & Parenting

My mom was 39 when I was born and 42 when my younger brother was born both naturally with no drugs or complications, and both of us were healthy and happy. The only thing I will say is my mom was noticibly "less fun" (read: less energy) than my friends' moms, who were often in their early-to-mid 30s when my mom was 50.

As others have mentioned though, there is this (overblown) line in many minds about age 35, so they will probably want to monitor the crap out of you. And there is a bit of a higher risk for chromosomal problems, like Downs. But if you are ok with that and unlikely to have a super early menopause, I say you know yourself best and it is better to wait until you are at a point where you are capable and mentally ready to support a baby. 40s are definitely not too late!

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.

sleep deprivation

Thu Sep 17 3:26 PM by robichek in Pregnancy & Parenting

Apparently there is a new book out called The Rabbit Who Wants to Go to Sleep and it is ALL THE RAGE.. ... 149617951X

If you are still breastfeeding, that may be an issue (not that I recommend that you stop breastfeeding). Topping up before they sleep could be warranted.

For my kid, we keep his room permanently dark and have a white-noise soundmaker outside his door and it works well. Also, although we didn't do a pure "cry it out" method, there were times at the beginning of his "sleep through the night" nights that he would wake up and whimper and we just would wait 2-10 minutes and he'd go back to sleep. That went away and now we don't expect a peep until at least 11 hours have passed. I think we as worried mothers are sort of complicit in creating their "need" for us.. If my boy knows I'll come in within 30 seconds of him making a sound, he'll want me to come in. If he's not sure how long it'll take, he'll go back to bed... Please take the preceding advice as something I might recommend only after the kid is 1 year old. Before then I would never just let him be... I used to rock him to sleep until my arms gave out.

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.