Genealogy date formats can be confusing. Dates are a critical part of family tree research. Making sure that we understand and verify the dates that we are recording is an important part of the historian's duties. I am confident that you have seen dates like 08/03/1995 where you are unsure whether the format refers to August 3 or March 8. This problem exists because countries around the world have not, until recently recorded a format for everyone to follow.
In Europe, dates are typically recorded dd-mm-yyyy. You may also find that family tree dates use similar formats to dd.mm.yy. In the United States, dates are recorded as mm-dd-yyyy or mm/dd/yyyy. Recently, the International Standards Organization introduced the ISO date standard format of yyyy-mm-dd. Using this notation will ensure that everyone knows 1995/08/03 is August third. There are a number all the advantages to using this format. A few are as follows:
- language independent
- can not be confused with other popular date notations
- consistency with the common 24h time notation system, where the larger units (hours) are also written in front of the smaller ones (minutes and seconds)
- strings containing a date followed by a time are also easily comparable and sortable (e.g. write "1995-02-04 22:45:00")
- the notation is short and has constant length, making data entry and table layout easier
- date notations with the order "year, month, day" are already widely used e.g. in Japan, Korea, Sweden, Finland, Denmark
- a 4-digit year representation avoids overflow problems after 2099-12-31. Check out the links on this website to find other resources and suggestions that will help you properly document the dates in your family tree.
Whether you have been working on your family tree for decades or just this week it is important to standardize the date format that you use. I recommend the International Standard (sometimes known as the ISO 8601) method of recording dates for all your genealogy documentation. Whether you are simply jotting down notes or recording dates on your source documents, using a consistent, reliable format will pay off in the future. After all, you are a family historian for your children and their children.
