How To Format Dates In Ancestry Trees (With Examples)

This article looks in detail at how to format dates in your Ancestry tree in a way that gives the most benefit to your family research.

Are you thinking: do Ancestry date formats really need a full article? Well, yes if you’ve ever scratched your head at these situations:

  • Different census records show different birth dates!”
  • All I have are the dates on the headstone.”
  • “I figure the birth date must be before 1820.”
  • The death date is either 1884 or 1885.
  • “It sucks that Ancestry wants ‘European’ dates!”

The Ancestry Date Format

The preferred Ancestry date format is dd mmm yyyy. For example, “11 Feb 1852”.

This is one of the few guidelines that Ancestry state clearly. It is also the standard genealogical format.

Just to be clear, I’m not banging a drum for a single universal correct date format. As a data specialist I follow ISO standard in my professional life, which is quite different (yyyy-mm-dd).

So why would you need a consistent date format at all? Particularly one that you may not be used to. Look at these entries from two different trees.

Which date format?

My guess is that Richard Smith was born on the 9th of June in Mississippi, USA. I’m guided by the fact that the majority of Ancestry users are from the USA. Personally, I must do mental gymnastics to “reverse” what my eyes are telling me.

And Elisabeth Hans was born 6th of September in a German location? Maybe. If I thought the second tree’s owner is actually European, I’d switch my guess to 9th of June. When we don’t know which tree owner is using which date format (and there are no sources), it’s quite possible that both these people share the same birth date.

If you’ve got a public tree, you’re probably interested in exchanging information with other genealogy hobbyists. The need for consistency is clear when trying to share and communicate with DNA matches and tree owners.

But maybe you have a private tree and wonder what benefit comes from a date format that is different to your day-to-day usage. The answer is Ancestry Search.

The Ancestry Date Format Helps Record Searches

Ancestry’s automated search functions deserve a chapter all of their own. I’ll keep it brief here.

Dates are recorded every which way in the billions of physical records that are the source of Ancestry’s digital archives. Genealogists review and determine which date format is most typical in a particular record collection.

The process that makes these records searchable must slice and dice a slew of different date formats into a day, a month, and a year. These three date-parts are then digitally stored in a standardized format.

As you build your tree, Ancestry’s automated search process tries to match your tree entries with its digital records. So here too, it must slice your date entry into a day, a month and a year to compare with the archives.

A bit of experimentation shows that there is some baked-in cleverness where Ancestry does try to “interpret” a non-standard date format in trees. I think it can figure out the day and month from something like “06/30/1905” where one of the two ambiguous figures are above 12.

But let’s go back to Richard and Elisabeth with date entries of 06/09/1905 and 09/06/1905. To prevent missing out on important records, it’s best not to feed ambiguous dates to any genealogical system. You simply avoid confusing Ancestry by using the date format of dd mmm yyyy.

Avoiding Flame Wars

I do steer clear of heated discussions on this topic.
These sometimes arise from an impression that Ancestry is favoring a “European” date format for all its customers.
The only possible reply to an assertion of “it’s my tree, I’ll do what I want” is: Of course it’s your tree and you can do what you want…

Problematic Entries

Here are six birth date entries I’ve pulled from public trees. From the point of view of a fellow researcher, I can make immediate sense of all but the first.

Not Ancestry date format

If you are puzzled by the “old calendar” reference – the birthplace is Poland and my guess is that the tree owner is referring to the Julian calendar.

If I work hard at interpreting that first date of “2 DEC 1717 // 22 // OCT // 1719, 1720”, my guess is that the tree owner has seen three possible dates across three years.

More importantly when Ancestry’s automated processes look for matching records – what does Ancestry guess? The right answer is: don’t make Ancestry guess.

So let’s work through how the tree owners could record the information they want to convey, while still getting the benefits of Ancestry Search.

How To Add Dates As Additional Sources

Often you’ll find that different sources show different dates for the same event. This is particularly the case when you are tracking a family through successive census records. The older census records are notoriously imprecise when it comes to age.

Let’s work a common example where your research finds a birth record and two census records – and all the dates are different.

The rule of thumb is to add a birth record as the main birth entry. The other dates can then be added as additional dates and sources. As usual with Ancestry, there are alternative ways to add alternative dates from the Profile page!

If you have added a birth record already, Ancestry may generate hints to various census records. Once you are satisfied Ancestry is showing you the correct record, you get the choice of choosing which census facts you want to add or overwrite into your tree. In our example, we’ve already added a birth record so we’re likely just to add the residency details. Both sources are clearly displayed on the profile but just one date is visible – like this:

How To Add Dates As Alternative Facts

You may want the birth year or date from a census record to show more clearly as an alternative date, particularly if its markedly different.

You may also want to add dates that are sourced elsewhere. The problematic entries I showed earlier mentioned sources such as a headstone or a family bible.

The Ancestry profile page lets you add facts manually and gives you a list of categories to choose from. The picture below shows the sequence for adding the details from a census record.

Add alternative facts

Headstones and Bible Sources

There isn’t a specific “bible” or “headstone” category, but you can record birth dates from these sources by choosing the “Birth” fact and adding a detailed description.
From here, you can upload a photograph to the Media section e.g. a headstone photo.

When you leave the “Preferred” box unchecked, this birth record is displayed as an alternative event.

How To Enter Approximate Dates

I also see a lot of variety around approximate dates. Ancestry list a few ways to record these in one of their help documents. They recommend using the word “before”, “after”, or “about” in front of the date. Then they say, “you can also use ca. (circa) to indicate an estimate.”

But if you play a little with data entry, you will notice that the type-ahead suggestions look for more consistency. If you hit enter, you can of course put in whatever you like. But below are the type-ahead formats for “before”, “after” and “about”. You will also find that if you type “circa”, the type-ahead is also “Abt.”.

about or circaAbt.

So we can be sure that the automated processes know what these particular abbreviations mean.

Having your own personal abbreviations would be a mistake. I have seen app, ap, and apx – presumably all for approximate, but it’s a tall order expecting automated Search to interpret unusual codes.

You may also see other family tree software handling “between” two dates. But Ancestry Search will not infer calculations in this way.

More Articles

Aside from dates, there are ways for formatting names and locations in your Ancestry tree that will benefit your research. We’ve got articles on both:


Margaret created a family tree on a genealogy website in 2012. She purchased her first DNA kit in 2017. She created this website to share insights and how-to guides on DNA, genealogy, and family research.

27 thoughts on “How To Format Dates In Ancestry Trees (With Examples)”

  1. I never realized there could be so much to consider with the dates. Thank you for the information and the process to add alternate dates.

  2. I have yet to figure out how to enter in between dates that Ancestry will accept without getting an “are you sure you want to use this” type of error message. How do you correctly enter a date if someone was born between 1078-1080? I’ve tried everything I can think of!

    • Are you using the Ancestry website? I just entered a date of 20 Nov 1078 in one of my private trees to test if there was a problem. I didn’t get an error message with the website. Are you using the mobile app, or desktop software?

      • The question is about how to input a range of dates. Say, you know that a person was alive in 1832 AND it was certainly dead by 1845. In other platforms, their date of death could be input as “between 1832 and 1845”

        • You can enter the phrase exactly as you have it: “between 1832 and 1845”.
          This will save exactly as this.
          However, it doesn’t help when searching i.e. when you’re searching within Ancestry, it doesn’t draw meaning in the way that some offline applications do.

  3. I think they mean that they only know that the date of birth is between these two dates and not more accurately.
    For instance if a person gives birth to a child in 1850 you may make an educated guess that they are between 15 and 50 (or some other limit) and so are born between 1800 and 1835.
    Also in the UK 1840 census, ages for adults are rounded to the nearest five years.
    If you have lots of people called Mary Smith in your tree, this range would be of more use to distinguish them than having lots of people with the same name and no dob to distinguish them. It will also allow people with similar dates of birth to be compared to see if they are actually the same person.

  4. I think the in-between thing isn’t possible right now in ancestry, which is really annoying. I have to create custom entries for start and end every time.
    Also, ancestry does not really understand the “After” Tag – it still uses the year as exact date. As a result, I had three siblings who suddenly all “died” in 1960, because I put “AFT 1960”.

  5. what about a date range?

    I have an ancestor that shows up in the census in 1865 for the last time.

    Then the earliest his wife shows up as widow of is 1869.

    Not sure if primary sources even exist that would show date of death.

    So logically I want to say for his death date: Between 1865 and 1869

    What would you do?

    • Some genealogy software have a “between” format. But Ancestry doesn’t have it on their list of recognized abbreviations and formats.
      Personally, I would use their approximate abbreviation which is “Abt.” and pick a date in the middle e.g. 1867. And then add a Comment to the profile explaining why I’m inferring the approximate date.

  6. What about B.C. dates? I’m trying to use this for ancestry dates in the Bible. I tried negative numbers, for BC, but doesn’t recognize that.

    • Ancestry doesn’t recognize negative numbers, but they do accept “B.C.” as an abbreviation *after* the date you enter. You’ll notice that if you enter BC (without the dots), they’ll change it to B.C.
      So this date is accepted (which is one year BC):
      1 Jan 1 B.C.

  7. Speaking of B.C., what if you only have a year to go by, such as 57 B.C.? From my experience, Ancestry finally accepts it after telling me there is an error, that I’m only entering a month. Also, it really throws off the Lifestory calculations, especially if someone was born in B.C. but died in A.D. In that case, it states that they were “minus” years old.

  8. Thanks. You start by listing the ISO yyyy mm dd as the only accurate and usable format and then go along with the dd mm yyyy as the standard.
    Considering all computer and software operations have to use machine ISO accurate and sortable format, why accept an inaccurate standard?
    The two real questions are,
    1) which software for genealogy accepts ISO 8106 entry and displays as an option;
    2) what is the workaround for Ancestry and Family Search?
    This is a bit like the old days when unicode was hard to find.

  9. Hi.
    Do you have any suggestions on dealing with Old Style dates? That is, back when the new year started on March 25?
    So for example, I have a baptism record dated 10 March 1664 in the original, where 1665 starts two weeks later on March 25. I’ve seen both “10 Mar 1664/5” and “10 Mar 1664 O.S.” used to denote this, but ancestry complains the former has too many days, and the latter has an invalid month.

    • Personally, I would have two baptismal facts. One with the data on the document, and then I would create a second (alternate) fact with the adjusted date. Also, add a comment or note to explain what’s going on.


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