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 November 11th, 2019.

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 October 7th, 2019 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Tuesday October 8th, 2019 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Wednesday October 9th, 2019 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Thursday October 10th, 2019 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Friday October 11th, 2019 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Saturday October 12th, 2019 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Sunday October 13th, 2019 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Monday October 14th, 2019 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Tuesday October 15th, 2019 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Wednesday October 16th, 2019 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Thursday October 17th, 2019 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Friday October 18th, 2019 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Saturday October 19th, 2019 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Sunday October 20th, 2019 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Monday October 21st, 2019 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Tuesday October 22nd, 2019 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Wednesday October 23rd, 2019 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Thursday October 24th, 2019 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Friday October 25th, 2019 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Saturday October 26th, 2019 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Sunday October 27th, 2019 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Monday October 28th, 2019 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Tuesday October 29th, 2019 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Wednesday October 30th, 2019 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Thursday October 31st, 2019 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Friday November 1st, 2019 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Saturday November 2nd, 2019 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Sunday November 3rd, 2019 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Monday November 4th, 2019 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Tuesday November 5th, 2019 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Wednesday November 6th, 2019 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Thursday November 7th, 2019 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Friday November 8th, 2019 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Saturday November 9th, 2019 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Sunday November 10th, 2019 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Monday November 11th, 2019 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Tuesday November 12th, 2019 40W, 1D 3.97% 53.98% -% -% 8.6% 25.1% 40.4% 54%
Wednesday November 13th, 2019 40W, 2D 3.91% 57.93% -% -% 9.3% 26.7% 42.5% 56.2%
Thursday November 14th, 2019 40W, 3D 3.81% 61.79% -% -% 10% 28.2% 44.5% 58.5%
Friday November 15th, 2019 40W, 4D 3.68% 65.54% -% -% 10.7% 29.8% 46.6% 60.6%
Saturday November 16th, 2019 40W, 5D 3.52% 69.15% -% -% 11.4% 31.3% 48.6% 62.7%
Sunday November 17th, 2019 40W, 6D 3.33% 72.57% -% -% 12.1% 32.9% 50.5% 64.7%
Monday November 18th, 2019 41W, 0D 3.12% 75.8% -% -% 12.9% 34.4% 52.4% 66.6%
Tuesday November 19th, 2019 41W, 1D 2.9% 78.81% -% -% 13.7% 36% 54.3% 68.5%
Wednesday November 20th, 2019 41W, 2D 2.66% 81.59% -% -% 14.4% 37.5% 56.1% 70.2%
Thursday November 21st, 2019 41W, 3D 2.42% 84.13% -% -% 15.2% 39% 57.9% 71.9%
Friday November 22nd, 2019 41W, 4D 2.18% 86.43% -% -% 16.1% 40.5% 59.6% 73.5%
Saturday November 23rd, 2019 41W, 5D 1.94% 88.49% -% -% 16.9% 42% 61.3% 75.1%
Sunday November 24th, 2019 41W, 6D 1.71% 90.32% -% -% 17.7% 43.4% 62.9% 76.4%
Monday November 25th, 2019 42W, 0D 1.5% 91.92% -% -% 18.6% 44.8% 64.5% 77.8%
Tuesday November 26th, 2019 42W, 1D 1.3% 93.32% -% -% 19.5% 46.3% 65.9% 79.2%
Wednesday November 27th, 2019 42W, 2D 1.11% 94.52% -% -% 20.3% 47.6% 67.3% 80.5%
Thursday November 28th, 2019 42W, 3D 0.94% 95.54% -% -% 21.1% 48.9% 68.8% 81.6%
Friday November 29th, 2019 42W, 4D 0.79% 96.41% -% -% 22% 50.1% 70.2% 82.7%
Saturday November 30th, 2019 42W, 5D 0.66% 97.13% -% -% 23% 51.6% 71.4% 83.6%
Sunday December 1st, 2019 42W, 6D 0.54% 97.72% -% -% 23.7% 53.1% 72.8% 84.6%
Monday December 2nd, 2019 43W, 0D 0.44% 98.21% -% -% 24.6% 54.2% 73.7% 85.5%
Tuesday December 3rd, 2019 43W, 1D 0.35% 98.61% -% -% 25.2% 55.4% 74.8% 86.3%
Wednesday December 4th, 2019 43W, 2D 0.28% 98.93% -% -% 26.2% 56.1% 75.7% 87.9%
Thursday December 5th, 2019 43W, 3D 0.22% 99.18% -% -% 26.8% 57.3% 76.8% -%
Friday December 6th, 2019 43W, 4D 0.18% 99.38% -% -% 29% 58.1% 79% -%
Saturday December 7th, 2019 43W, 5D 0.14% 99.53% -% -% 29.8% 59.6% -% -%
Sunday December 8th, 2019 43W, 6D 0.1% 99.65% -% -% 28.6% 62.9% -% -%
Monday December 9th, 2019 44W, 0D 0.08% 99.74% -% -% 30.8% -% -% -%
Tuesday December 10th, 2019 44W, 1D 0.06% 99.81% -% -% 31.6% -% -% -%
Wednesday December 11th, 2019 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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